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Publisher: Elsevier   (Total: 2800 journals)

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The American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3)
The American J. of Surgery     Hybrid Journal   (Followers: 24, SJR: 1.328, h-index: 114)
The Arts in Psychotherapy     Hybrid Journal   (Followers: 6)
The Breast     Hybrid Journal   (Followers: 6)
The British Accounting Review     Hybrid Journal   (Followers: 6, SJR: 0.634, h-index: 34)
The Chemical Physics of Solid Surfaces     Full-text available via subscription  
The Cytoskeleton: A Multi-Volume Treatise     Full-text available via subscription  
The Electricity J.     Partially Free   (Followers: 3, SJR: 0.517, h-index: 25)
The Enzymes     Full-text available via subscription   (Followers: 1, SJR: 0.339, h-index: 7)
The Extractive Industries and Society     Hybrid Journal  
The Foot     Hybrid Journal   (Followers: 8)
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The History of Neuroscience in Autobiography     Full-text available via subscription   (Followers: 1)
The Internet and Higher Education     Hybrid Journal   (Followers: 74, SJR: 2.565, h-index: 40)
The Intl. J. of Accounting     Hybrid Journal   (Followers: 1)
The Intl. J. of Biochemistry & Cell Biology     Hybrid Journal   (Followers: 4, SJR: 2.423, h-index: 128)
The J. for Nurse Practitioners     Hybrid Journal   (Followers: 4, SJR: 0.136, h-index: 7)
The J. of Arthroplasty     Hybrid Journal   (Followers: 41)
The J. of Chemical Thermodynamics     Hybrid Journal   (Followers: 3, SJR: 1.292, h-index: 52)
The J. of Foot and Ankle Surgery     Full-text available via subscription   (Followers: 10)
The J. of Hand Surgery     Full-text available via subscription   (Followers: 32)
The J. of Heart and Lung Transplantation     Hybrid Journal   (Followers: 5, SJR: 2.881, h-index: 86)
The J. of High Technology Management Research     Hybrid Journal   (Followers: 1, SJR: 0.245, h-index: 26)
The J. of Logic and Algebraic Programming     Hybrid Journal   (Followers: 2, SJR: 0.647, h-index: 38)
The J. of Mathematical Behavior     Hybrid Journal   (Followers: 1, SJR: 0.766, h-index: 24)
The J. of Molecular Diagnostics     Hybrid Journal   (Followers: 1, SJR: 1.974, h-index: 57)
The J. of Nutritional Biochemistry     Hybrid Journal   (Followers: 1, SJR: 1.627, h-index: 88)
The J. of Pain     Hybrid Journal   (Followers: 9)
The J. of Pediatrics     Hybrid Journal   (Followers: 80)
The J. of Prosthetic Dentistry     Full-text available via subscription   (Followers: 2)
The J. of Socio-Economics     Hybrid Journal   (Followers: 5, SJR: 0.356, h-index: 29)
The J. of Strategic Information Systems     Hybrid Journal   (Followers: 15, SJR: 2.903, h-index: 50)
The J. of Supercritical Fluids     Hybrid Journal   (Followers: 3, SJR: 1.141, h-index: 69)
The J. of the American College of Certified Wound Specialists     Hybrid Journal   (Followers: 1, SJR: 0.14, h-index: 3)
The J. of Thoracic and Cardiovascular Surgery     Hybrid Journal   (Followers: 6, SJR: 2.268, h-index: 143)
The J. of Urology     Full-text available via subscription   (Followers: 58)
The Kaohsiung J. of Medical Sciences     Full-text available via subscription  
The Knee     Hybrid Journal   (Followers: 14, SJR: 1.137, h-index: 44)
The Lancet     Full-text available via subscription   (Followers: 1352, SJR: 11.563, h-index: 514)
The Lancet Diabetes and Endocrinology     Full-text available via subscription   (Followers: 18)
The Lancet Global Health     Open Access   (Followers: 23)
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The Lancet Psychiatry     Full-text available via subscription   (Followers: 10)
The Lancet Respiratory Medicine     Full-text available via subscription   (Followers: 10)
The Leadership Quarterly     Hybrid Journal   (Followers: 41, SJR: 2.069, h-index: 76)
The North American J. of Economics and Finance     Hybrid Journal   (Followers: 1, SJR: 0.667, h-index: 20)
The Quarterly Review of Economics and Finance     Hybrid Journal   (Followers: 13, SJR: 0.565, h-index: 26)
The Social Science J.     Hybrid Journal   (Followers: 4, SJR: 0.255, h-index: 18)
The Spine J.     Hybrid Journal   (Followers: 12, SJR: 1.493, h-index: 62)
The Surgeon     Hybrid Journal   (Followers: 1, SJR: 0.784, h-index: 25)
The Veterinary J.     Hybrid Journal   (Followers: 10, SJR: 1.005, h-index: 63)
Theoretical and Applied Fracture Mechanics     Hybrid Journal   (Followers: 6, SJR: 1.179, h-index: 35)
Theoretical and Computational Chemistry     Full-text available via subscription   (Followers: 7)
Theoretical Computer Science     Hybrid Journal   (Followers: 4, SJR: 0.932, h-index: 74)
Theoretical Ecology Series     Full-text available via subscription   (Followers: 1)
Theoretical Population Biology     Hybrid Journal   (Followers: 12, SJR: 0.973, h-index: 61)
Theriogenology     Hybrid Journal   (Followers: 2, SJR: 1.059, h-index: 89)
Thermochimica Acta     Hybrid Journal   (Followers: 16, SJR: 0.645, h-index: 77)
Thin Films and Nanostructures     Full-text available via subscription   (Followers: 3)
Thin Solid Films     Hybrid Journal   (Followers: 9, SJR: 0.884, h-index: 130)
Thin-Walled Structures     Hybrid Journal   (Followers: 1, SJR: 1.786, h-index: 38)
Thinking Skills and Creativity     Hybrid Journal   (Followers: 11, SJR: 0.709, h-index: 15)
Thoracic Surgery Clinics     Full-text available via subscription   (Followers: 1, SJR: 0.311, h-index: 35)
Thrombosis Research     Hybrid Journal   (Followers: 25, SJR: 1.098, h-index: 80)
Ticks and Tick-borne Diseases     Hybrid Journal   (Followers: 5, SJR: 0.943, h-index: 12)
Tissue and Cell     Hybrid Journal   (Followers: 2, SJR: 0.464, h-index: 35)
Topics in Companion Animal Medicine     Hybrid Journal   (Followers: 1, SJR: 0.521, h-index: 28)
Topics in Inorganic and General Chemistry     Full-text available via subscription  
Topology     Full-text available via subscription  
Topology and its Applications     Full-text available via subscription   (SJR: 0.663, h-index: 28)
Tourism Management     Hybrid Journal   (Followers: 10, SJR: 1.961, h-index: 80)
Tourism Management Perspectives     Hybrid Journal   (Followers: 1, SJR: 0.476, h-index: 4)
Toxicologie Analytique et Clinique     Full-text available via subscription  
Toxicology     Hybrid Journal   (Followers: 13, SJR: 1.196, h-index: 105)
Toxicology and Applied Pharmacology     Hybrid Journal   (Followers: 12, SJR: 1.429, h-index: 117)
Toxicology in Vitro     Hybrid Journal   (Followers: 7, SJR: 0.923, h-index: 63)
Toxicology Letters     Hybrid Journal   (Followers: 8, SJR: 1.098, h-index: 101)
Toxicology Reports     Open Access  
Toxicon     Hybrid Journal   (Followers: 3, SJR: 1.008, h-index: 88)
TrAC Trends in Analytical Chemistry     Full-text available via subscription   (Followers: 20, SJR: 2.325, h-index: 103)
Trace Metals and other Contaminants in the Environment     Full-text available via subscription   (Followers: 2, SJR: 0.101, h-index: 5)
Trace Metals in the Environment     Full-text available via subscription   (Followers: 2)
Transactions of Nonferrous Metals Society of China     Hybrid Journal   (Followers: 8, SJR: 0.893, h-index: 27)
Transfusion and Apheresis Science     Hybrid Journal   (SJR: 0.56, h-index: 37)
Transfusion Clinique et Biologique     Full-text available via subscription   (Followers: 1, SJR: 0.396, h-index: 30)
Transfusion Medicine Reviews     Hybrid Journal   (Followers: 1, SJR: 1.821, h-index: 48)
Translational Oncology     Open Access   (SJR: 1.282, h-index: 23)
Translational Proteomics     Open Access  
Translational Research     Full-text available via subscription   (Followers: 3, SJR: 1.443, h-index: 66)
Transplant Immunology     Hybrid Journal   (Followers: 2, SJR: 0.717, h-index: 48)
Transplantation Proceedings     Hybrid Journal   (Followers: 2, SJR: 0.481, h-index: 63)
Transplantation Reviews     Hybrid Journal   (Followers: 6, SJR: 0.843, h-index: 25)
Transport Policy     Hybrid Journal   (Followers: 9, SJR: 1.666, h-index: 40)
Transportation Geotechnics     Full-text available via subscription   (Followers: 1)
Transportation Research Part A: Policy and Practice     Hybrid Journal   (Followers: 30, SJR: 2.433, h-index: 65)
Transportation Research Part B: Methodological     Hybrid Journal   (Followers: 28, SJR: 3.306, h-index: 70)

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Journal Cover   Catalysis Today
  [SJR: 1.378]   [H-I: 142]   [6 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0920-5861
   Published by Elsevier Homepage  [2800 journals]
  • Plasma-catalytic dry reforming of methane in an atmospheric pressure AC
           gliding arc discharge
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Zaenab Abd Allah, J. Christopher Whitehead
      The combination of a gliding arc discharge with a catalyst has been investigated as a means of optimising the dry reforming process for methane with carbon dioxide in respect of increased methane and carbon dioxide conversion and hydrogen yield. A bed of NiO/Al2O3 catalyst (18% or 33% NiO loading) was placed downstream of an atmospheric pressure gliding arc discharge in an equimolar CH4/CO2 mixture. The catalyst bed was in contact with the luminous afterglow of the discharge. This arrangement enhances methane and carbon dioxide conversions and increases the hydrogen yield by up to 30%. It was noted that hydrogen yields were greater for a lower NiO loading (18% compared to 33%) and that a smaller particle size is also beneficial. The energy efficiency is increased by over 20% by the addition of a catalyst.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Plasma-catalytic dry reforming of methane over γ-Al2O3 supported
           metal catalysts
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Yuxuan Zeng, Xinbo Zhu, Danhua Mei, Bryony Ashford, Xin Tu
      A coaxial dielectric barrier discharge (DBD) reactor has been developed for plasma-catalytic dry reforming of CH4 and CO2 into higher value synthesis gas (syngas). The influence of reaction conditions (e.g. CO2/CH4 molar ratio and total feed flow rate) and supported metal catalysts M/γ-Al2O3 (M=Ni, Co, Cu and Mn) on the performance of the plasma process has been investigated in terms of the conversion of feed gases, the selectivity and yield of major gas products, and the energy efficiency of the plasma process. The combination of plasma with the Ni/γ-Al2O3 and Mn/γ-Al2O3 catalysts significantly enhanced the conversion of CH4 and exhibited a plasma-catalytic synergy for this and the overall energy efficiency of the process. The maximum CH4 conversion of 19.6% was achieved for the plasma-catalytic dry reforming over the Ni/γ-Al2O3 catalyst at a discharge power of 7.5W and a gas flow rate of 50mlmin−1. However, the presence of any of these catalysts in the plasma did not show any synergy for CO2 conversion. In addition, the integration of plasma and the γ-Al2O3 supported catalysts was found to enhance the yield of CO and H2, whilst the Ni/γ-Al2O3 catalyst exhibited the best activity for syngas production.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Pulsed dry methane reforming in plasma-enhanced catalytic reaction
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Seigo Kameshima, Keishiro Tamura, Yutaro Ishibashi, Tomohiro Nozaki
      Pulsed dry methane reforming (DMR) in dielectric barrier discharge (DBD) and 12wt.% Ni/Al2O3 catalyst hybrid reaction was investigated, aiming for efficient conversion of greenhouse gas (CH4, CO2) into syngas (H2, CO) at low temperature. CO2 was continuously supplied, while CH4 was introduced intermittently for 1min at constant interval of 3min. Although solid carbon was deposited during the reforming reaction, carbon was almost fully removed by turning off CH4 flow and applying CO2-fed DBD. Pulsed transient analysis revealed that CH4 dehydrogenation and subsequent reverse water–gas-shift reaction is sufficiently fast with and without DBD, producing syngas with the H2/CO ratio of 0.8–0.9. In contrast, carbon removal reaction, i.e. Boudouard reaction, is promoted clearly by DBD hybridization. Radical injection is primarily important step. Besides, selective surface heating by DBD such as charge recombination on the catalysts is anticipated to promote carbon diffusion through Ni catalyst particles and subsequent oxidation by adsorbed CO2. DBD and catalyst hybrid reaction enabled higher CH4 and CO2 conversion without having serious coking problem.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Plasma N2-fixation: 1900–2014
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): B.S. Patil, Q. Wang, V. Hessel, J. Lang
      Nitrogen is the most basic element responsible for the growth of living creatures on earth. Chemical nitrogen fixation process is one of the most important chemical processes, which sustains the growing global population. Wherein the life changing Haber-Bosch process comes into the picture, which produces more than 130 million tons of ammonia per year by consuming ∼1–2% of the world's total energy consumption and sustains ∼40% of the world's population. Several efforts have been invested to develop an energy efficient alternative to this not-so-environmentally-friendly process. Nitric oxide and ammonia synthesis, with plasma as an alternative energy form, have been investigated extensively over the last 100 years. This review covers the important findings in the field of plasma nitrogen fixation and critically analyzes the studies reported from 1900 to 2014.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Design of efficient Fischer Tropsch cobalt catalysts via plasma
           enhancement: Reducibility and performance (Review)
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Wei Chu, Junqiang Xu, Jingping Hong, Tao Lin, A. Khodakov
      In this paper, several types of plasma enhanced catalysts for Fischer Tropsch (FT) synthesis were investigated and discussed, in comparison of conventional catalysts, with different carriers [alumina, silica, carbon nanotubes (CNTs)], and/or different promoters (Pt, Ru), etc. For the silica-supported cobalt FT catalysts, the cobalt dispersion was significantly enhanced by plasma treatment. Nano cobalt particle size was smaller when the glow discharge plasma intensity was higher. There were similar cases for the Ru promoted FT catalysts or alumina supported FT catalysts. For the alumina supported cobalt FT catalysts, Pt addition enhanced significantly the catalysts reduction. Due to the combination of higher cobalt dispersion and optimized cobalt reducibility, plasma-assisted promoted catalysts exhibited an enhanced activity in FT synthesis.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Atmospheric-pressure O2 plasma treatment of Au/TiO2 catalysts for CO
           oxidation
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Shuo Zhang, Xiao-Song Li, Bin Zhu, Jing-Lin Liu, Xiaobing Zhu, Ai-Min Zhu, Ben W.-L. Jang
      Atmospheric-pressure O2 plasma generated by dielectric barrier discharge (DBD) is applied to treat Au/TiO2 catalysts synthesized via the deposition–precipitation method for CO oxidation. The plasma-treated sample (S-P) presents a higher activity than the calcined one (S-C). To elucidate the plasma treatment effect, XPS, TEM/HRTEM, sub-ambient pulse CO chemisorption and in situ DRIFTS techniques were used for catalyst characterization. In comparison with S-C, TEM/HRTEM reveals that the S-P catalyst has small particle size and narrow size distribution; XPS and DRIFTS analyses indicate plentiful surface hydroxyl groups on S-P sample. Pulse CO chemisorption and in situ DRIFTS of CO adsorption show that significant increase of low-coordinated Au species has been achieved by the plasma treatment. The improved activity of S-P is ascribed to large amount of low-coordinated Au species and interface active sites as well as abundant surface hydroxyl groups.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Dielectric barrier discharge plasma for preparation of Ni-based catalysts
           with enhanced coke resistance: Current status and perspective
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Xiaoliang Yan, Binran Zhao, Yuan Liu, Yanan Li
      Ni-based catalysts show high activity for steam or CO2 reforming of methane, partial oxidation of methane, and CO or CO2 methanation. However, a challenge that Ni catalysts are facing is the high thermodynamic potential for carbon deposition, derived from CO disproportionation or CH4 decomposition. Coke deposition causes reactor blockage, and the formed carbon filaments lead to the deformation of the catalyst. Encapsulating carbon quickly induces the deactivation of Ni catalysts. In this perspective, the preparation methods for the Ni catalysts were studied by dielectric barrier discharge (DBD) plasma and thermal decomposition. The DBD plasma decomposition method and the mechanism for the preparation of the catalysts were introduced. Different Ni structures were produced by different preparation methods. The geometric structure over the Ni catalysts played an important role on carbon deposition rate and carbon morphology. DBD plasma decomposed Ni catalysts possessed improved coke resistance. The reactivity of the carbon was studied toward temperature programmed surface reaction. This perspective provides the understanding of Ni-based catalysts with coke resistance and gives the relationship of Ni structure and carbon formation.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Nanoscale thermodynamic aspects of plasma catalysis
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Erik C. Neyts, Kostya (Ken) Ostrikov
      Plasma catalysis continues to gain increasing scientific interest, both in established fields like toxic waste abatement and emerging fields like greenhouse gas conversion into value-added chemicals. Attention is typically focused on the obtained conversion process selectivity, rates and energy efficiency. Much less attention is usually paid to the underlying mechanistic aspects of the processes that occur. In this contribution, we critically examine a number of fundamentally important nanoscale thermodynamic aspects of plasma catalysis, which are very relevant to these processes but so far have been overlooked or insufficiently covered in the plasma catalysis literature.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • A multidisciplinary approach to understand the interactions of nonthermal
           plasma and catalyst: A review
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Hyun-Ha Kim, Yoshiyuki Teramoto, Nobuaki Negishi, Atsushi Ogata
      Low temperature catalytic reactions induced by nonthermal plasma (NTP) have been of great interest in plasma chemistry for application to pollution control and energy-related issues. Current progress in the experimental observations and the understanding of interactions between NTP and catalyst are reviewed herein. Considering the diffusion length and lifetime of reactive species, we introduced a dimensionless parameter Λ that describes the criteria for a direct interaction between NTP and catalysts. Several lines of experimental evidences on the interaction were introduced: discharge mode, formation of metal cluster ions, and plasma-induced fluorescence from the catalyst. For faujasite zeolites, the Si/Al ratio was found to be an important parameter that determines the propagation of surface streamers and catalytic performance. The oxidation status of metals is closely correlated with the Si/Al ratio, which is related to substantial changes in electrical resistivity.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Mechanism of template removal for the synthesis of molecular sieves using
           dielectric barrier discharge
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Yuan Liu, Zhao Wang, Chang-jun Liu
      Molecular sieves are extensively employed in catalysis, separation and many other fields. Various organic templates are commonly applied for the synthesis of molecular sieves. However, thermal treatment has to be conducted at elevated temperature to remove the template after synthesis. The high temperature operation may destroy the structure of molecular sieves. A dielectric-barrier discharge (DBD) plasma technique, initiated at ambient conditions, was recently developed for the quick, safe and easy removal of templates from molecular sieves. In this work, the mechanism of DBD plasma template removal is investigated. The study confirms that dissociation of template molecule by active species (like electrons and excited oxygen species) and oxidation of radicals (from the dissociation) by active oxygen species (like ozone and excited oxygen species) are the mechanism of the DBD plasma enhanced template removal. The thermal image confirms that the DBD plasma template removal is conducted under temperature around 125°C. The thermal effect can be ignored. The present study is leading to a unique way for the syntheses of various micro- and meso-porous materials.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Steam reforming of methane over Ni/SiO2 catalyst with enhanced coke
           resistance at low steam to methane ratio
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Yao Zhang, Wei Wang, Zongyuan Wang, Xintong Zhou, Zhao Wang, Chang-Jun Liu
      Dielectric barrier discharge (DBD) plasma was applied for the decomposition of nickel nitrate under air at ∼150°C. Calcination (at 500°C) under air and hydrogen reduction (at 500°C) thermally were then conducted. The obtained Ni/SiO2 catalyst was investigated for steam reforming of methane (SRM) at the reaction temperatures of 600, 700 and 800°C with a very low steam to methane molar ratio (H2O/CH4 =0.5), in order to test the coke resistance of the catalyst. The DBD plasma prepared catalyst possesses an average particle size of 5.5nm, much smaller than 15.3nm of the thermally calcined one. The smaller catalyst size can lead to an enhanced coke resistance over the plasma prepared catalyst. The carbon nanotubes obtained on the used plasma prepared catalyst are very different from those formed on the calcined catalyst. The plasma decomposition is excellent for further investigation of effect of the catalyst structure beyond the nickel catalyst.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Pt-free, non-thermal plasma-assisted NOx storage and reduction over
           M/Ba/Al2O3 (M=Mn, Fe, Co, Ni, Cu) catalysts
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Zhao-Shun Zhang, Mark Crocker, Bing-Bing Chen, Zhi-Feng Bai, Xin-Kui Wang, Chuan Shi
      Based on their high NO x storage capacities (NSCs), a series of M/Ba/Al (M=Mn, Fe, Co, Ni, Cu) catalysts were evaluated in NO x storage-reduction catalysis. Although the M/Ba/Al catalysts exhibited high NSC values, they exhibited much lower activity during lean-rich cycling compared with a traditional Pt/Ba/Al catalyst, indicating that regeneration of stored NO x is the rate limiting step for the M/Ba/Al samples. By employing an H2-plasma in the rich phase to assist reduction of the stored NO x , the NO x conversion was greatly improved, especially at low temperature.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • CO2 reforming of methane over Mn promoted Ni/Al2O3 catalyst treated by N2
           glow discharge plasma
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Fang Guo, Jun-Qiang Xu, Wei Chu
      The N2 plasma treated Ni/Al2O3 catalyst was enhanced by manganese (Mn) promoter with doping content ranging from 5wt% to 15wt%. Compared to the plasma treated nickel catalyst without Mn additive, the introduction of Mn promoter further increased the CH4 conversion of studied catalysts about 10% at 700°C for CO2 reforming of methane. After 360min reaction of time-on-stream, the deactivation degree value was decreased to 1.46%. Relatively lower value of 5–10wt% doping amount of Mn was appropriate. Mn promoter further intensified the reducibility of plasma treated catalyst according to the shift to lower temperature of the reduction peak shown in H2-TPR profiles. CO2-TPD results suggested that the modification effect of Mn promoter on the basicity of plasma treated catalyst was speculated to account for the concentration increase of absorbed CO2. It was beneficial to the carbon deposition elimination and it increased the coking-resistant ability of catalyst surface, while this result was in good agreement with the CO2-TPSR and TG results. The lower temperature and smaller area of CO peak was observed over plasma treated Ni-Mn/Al2O3 catalyst in CO2-TPSR test, i.e., less coke formation on the Mn promoted sample.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Catalyst screening for acetone removal in a single-stage plasma-catalysis
           system
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Xinbo Zhu, Xiang Gao, Xinning Yu, Chenghang Zheng, Xin Tu
      Plasma-catalytic removal of acetone over MO x /γ-Al2O3 (M=Ce, Co, Cu, Mn and Ni) catalysts has been investigated in a dielectric barrier discharge (DBD) reactor. The influence of different catalysts on the plasma-catalytic process has been examined in terms of acetone removal efficiency, CO2 selectivity and the formation of by-products. The combination of plasma with the MO x /γ-Al2O3 catalysts significantly enhances the removal efficiency of acetone and CO2 selectivity, whilst substantially reducing the formation of by-products (HCHO and HCOOH). The maximum removal efficiency of 94.2% and CO2 selectivity of 80.1% were achieved when using the CuO x /γ-Al2O3 catalyst. Introducing the CuO x /γ-Al2O3 catalyst into the plasma system also shows the lowest formation of by-products. Different catalyst characterization techniques have been used to understand the effect of catalyst properties on the plasma reactions. It has been found that the reducibility of the MO x /γ-Al2O3 catalysts plays a dominant role in the plasma-catalytic oxidation of acetone, whilst the specific surface area and pore properties of the catalysts have a very weak effect on the performance of the plasma-catalytic reaction. In addition, a simplified kinetic model has been developed, showing the effect of different catalysts on the acceleration of the plasma-catalytic removal of acetone.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Catalytic nonthermal plasma assisted co-processing of methane and nitrous
           oxide for methanol production
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Sk. Mahammadunnisa, K. Krushnamurty, Ch. Subrahmanyam
      The objective of the present study is the direct conversion of potential greenhouse gases methane (CH4) and nitrous oxide (N2O) into value added products like methanol, syngas, etc. in a nonthermal plasma reactor operated under ambient conditions. Typical results indicated that co-processing of the reactants has an advantage of in-situ decomposition of N2O into N2 and atomic oxygen that favors methane partial oxidation to methanol. In order to improve the selectivity to methanol, plasma reactor was operated by integrating CuO/CeO2, NiO/CeO2 and Cu-Ni (5-5)/CeO2 catalysts. Among the studied catalysts, Cu-Ni (5:5wt%) supported on ceria showed the best selectivity of ∼36% to methanol.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Post-plasma catalytic oxidative CO2 reforming of methane over Ni-based
           catalysts
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Kai Li, Jing-Lin Liu, Xiao-Song Li, Xiao-Bing Zhu, Ai-Min Zhu
      To seek an efficient route for syngas production from oxidative CO2 reforming of methane (OCRM) via post-plasma catalytic technique, three routes were compared using spark-shade plasma (input power=106W, with F1 of 1.36 SLM at CH4:O2:CO2 =1:0.6:0.7) and Ni/CeO2/Al2O3 catalyst (catalyst temperature=800°C, with or without F2 of 0.52 SLM CH4). Compared with Route 1 (plasma only, F1 only), X O 2 , X CH 4 , C H 2 + CO and H2/CO ratio of Route 2 (plasma+catalyst, F1 only) increased to 100%, 99%, 76% and 1.2, respectively; but X CO 2 kept at about 35%, which was close to the thermodynamic-equilibrium values. In Route 3 (plasma+catalyst, F1+F2), X CO 2 increased dramatically to 67%, C H 2 + CO and H2/CO ratio further increased to 86% and 1.5, respectively, though X CH 4 decreased to 77%. Both S CO and S H 2 arrived at nearly 100%. Assuming that the plasma could supply the heat energy for the subsequent catalytic reaction at 800°C, syngas energy cost as low as 0.5eV/molecule and energy efficiency as high as 91% were achieved.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Combination of plasmas and catalytic reactions for CO2 reforming of CH4 by
           dielectric barrier discharge process
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Hoang Hai Nguyen, Kyo-Seon Kim
      Dry reforming of methane that converts two green-house gases (CH4 and CO2) to syngas (mixture of CO and H2) has gained a great research interests. In this research, we investigated the CO2 reforming of CH4 to syngas by the combination of dielectric barrier discharge (DBD) plasmas and zeolite catalyst particles, which was effective in converting the CO2 and CH4 into syngas. The effects of peak voltage applied to plasmas, total gas flow rate and input CO2/CH4 molar ratio on CO2 and CH4 conversions and H2 and CO selectivities were investigated. The product gases were mainly composed of H2 and CO with some generation of by-products. The conversion efficiencies of CO2 and CH4 in DBD plasmas with zeolite catalyst increased by the increase of voltage applied to plasmas. The selectivities of CO and H2 depend largely on the voltage applied to the plasmas and the ratio of CO2 to CH4, but did not depend significantly on the changes of frequency and total gas flow rate.
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      PubDate: 2015-08-21T15:04:50Z
       
  • IFC - Editorial Board
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1




      PubDate: 2015-08-21T15:04:50Z
       
  • Contents list
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1




      PubDate: 2015-08-21T15:04:50Z
       
  • Plasmas for enhanced catalytic processes (ISPCEM 2014)
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Tomohiro Nozaki, Erik C. Neyts, Mohan Sankaran, Kostya (Ken) Ostrikov, Chang-Jun Liu



      PubDate: 2015-08-21T15:04:50Z
       
  • Molecular dynamics simulations of supported metal nanocatalyst formation
           by plasma sputtering
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Pascal Brault, Erik C. Neyts
      Magnetron sputtering is a widely used physical vapor deposition technique for deposition and formation of nanocatalyst thin films and clusters. Nevertheless, so far only few studies investigated this formation process at the fundamental level. We here review atomic scale molecular dynamics simulations aimed at elucidating the nanocatalyst growth process through magnetron sputtering. We first introduce the basic magnetron sputtering background and machinery of molecular dynamics simulations, and then describe the studies conducted in this field so far. We also present a perspective view on how the field may be developed further.
      Graphical abstract image

      PubDate: 2015-08-21T15:04:50Z
       
  • Atmospheric-pressure cold plasma for fabrication of anatase–rutile
           mixed TiO2 with the assistance of ionic liquid
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Xiuling Zhang, Lijuan Zhang, Yanchun Li, Lanbo Di
      An atmospheric-pressure dielectric barrier discharge (DBD) gas–liquid cold plasma was employed to synthesize TiO2 nanoparticles in an aqueous solution, with the assistance of nine imidazolium-based ionic liquids and using air as working gas. X-ray diffraction, N2 adsorption–desorption measurements, and transmission electron microscopy were used to characterize the samples. The results showed that the samples prepared by the DBD gas–liquid cold plasma were anatase–rutile mixed TiO2 with mesoporous structures. The effects of the cations, anions, and the amount of the ionic liquids on the structure of the TiO2 samples were investigated, and the corresponding mechanism of actions were analyzed. The photocatalytic activity of the TiO2 photocatalysts was evaluated by photodegradation of methylene blue. The TiO2 prepared with the assistance of 0.2ml 1-ethyl-3-methylimidazolium tetrafluoroborate in Ti precursor solution exhibited the highest photocatalytic activity. Atmospheric-pressure DBD cold plasma was found to be a fast, simple, and environmentally friendly method for fabricating mixed-phase TiO2.
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      PubDate: 2015-08-21T15:04:50Z
       
  • Growth of graphene films on Cu catalyst in hydrogen plasma using
           polymethylmethacrylate as carbon source
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Miaoling Huang, Yi Zhang, Chundong Wang, Jian-Guo Ren, Qi-Hui Wu, Qing-Biao Li
      Owing to its excellent electronic characteristics and wide spectrum of potential applications, graphene has attracted intense attention by not only scientists but also engineers. Growth of graphene films on copper foils using gaseous carbon sources has been emphasized previously due to the high quality/price ratio. In this study, we reported the synthesis of graphene films on copper substrate converting from a solid carbon source (polymethylmethacrylate) with help of hydrogen plasma. The effects of substrate temperature and microwave power on the growth of graphene have been investigated. Raman spectroscopic data indicated that high microwave power and substrate temperature would benefit the growth of high quality graphene films. X-ray photoelectron spectroscopic results implied that the synthesized graphene films were in high purity with small amount of oxygen contaminations. Transmission electron microscopy data suggested that the synthesized graphene films are polycrystalline and its atomic arrangement is in short-range order.
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      PubDate: 2015-08-21T15:04:50Z
       
  • Synthesis of metallic Ni-Co/graphene catalysts with enhanced
           hydrodesulfurization activity via a low-temperature plasma approach
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Xuzhen Wang, Wenya Xu, Ning Liu, Zhengfa Yu, Yong Li, Jieshan Qiu
      Graphene sheets (GS) supported monometal (Ni, Co) or bimetal (Ni-Co) nanoparticle composites have been conveniently prepared with the assistance of dielectric barrier discharge (DBD) plasma at low temperature. Both graphene oxide and the metal ions (Ni2+, Co2+) can be simultaneously reduced during the DBD plasma treatment in H2 atmosphere, which gives rise to the uniformly distributed metal nanoparticles on the surface of GS. The graphene-based catalysts are used in the catalytic hydrodesulfurization (HDS) of carbonyl sulfide (COS). It is revealed that the bimetallic Ni-Co/GS catalyst exhibits outstanding performance for higher COS conversion compared with the monometal catalysts, suggesting the synergetic effect between Ni and Co active species in the HDS reaction. The presented strategy demonstrates a new pathway for the preparation of graphene-based catalysts with high HDS catalytic performance.
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      PubDate: 2015-08-21T15:04:50Z
       
  • Certain nitrogen functionalities on carbon nanofiber support for improving
           platinum performance
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Chengxu Zhang, Jue Hu, Xiaodong Zhang, Xiangke Wang, Yuedong Meng
      Nitrogen (N) modification of carbon nanomaterial, which plays a critical role in improving platinum (Pt) performance, has shown fascinating applications. N-doped carbon nanofiber (CNF)-supported platinum catalysts were produced by an approach combined of plasma-enhanced chemical vapor deposition and in situ plasma activation. This approach can successfully introduce nitrogen functionalities into a carbon network, and at the same time, preserve the highly graphitic structure of the carbon support. XPS results indicate that NH3 plasma modification mainly creates pyridinic nitrogen functionalities, while N2 plasma modification mainly increases the percentage of pyrrolic nitrogen in the carbon network, which suggests a modification of certain nitrogen functionalities on the carbon support. By correlating TEM and XPS data with electrochemical measurements, we conclude that the N-modified CNF exhibits a significant improvement in Pt electrochemical activity and stability than pristine CNF support and Pt/CNF–NH3 electrode with smallest Pt particle size, highest percentage of pyridinic nitrogen, exhibits the highest Pt utilization, electrochemical activity, and poisoning-resistance ability. Our study gives both insights on the influence of N modification of the carbon support in platinum catalytic effectiveness and a route for formation of certain nitrogen functionalities on the carbon support. This will be important for the further development of Pt catalysts.
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      PubDate: 2015-08-21T15:04:50Z
       
  • Pd/PdO nanoparticles supported on carbon nanotubes: A highly effective
           catalyst for promoting Suzuki reaction in water
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Fan Yang, Cheng Chi, Sen Dong, Chunxia Wang, Xilai Jia, Liang Ren, Yunhan Zhang, Liqiang Zhang, Yongfeng Li
      We report that the presence of PdO nanoparticles can enhance the catalytic performance of Pd catalyst for the Suzuki reaction in water. Heterogeneous Pd/PdO nanoparticles supported on multi-walled carbon nanotubes (CNTs), weakly oxidized multi-walled carbon nanotubes (WCNTs) and strongly oxidized multi-walled carbon nanotubes (SCNTs) catalysts are synthesized by a one-pot gas–liquid interfacial plasma (GLIP) method using Pd(NO3)2·2H2O as precursor. Among these synthesized catalysts, the Pd/PdO supported on WCNTs (Pd/PdO/WCNTs) catalyst exhibits the highest catalytic activity during the Suzuki reaction in water. Moreover, the Pd/PdO catalyst shows higher catalytic activity during the Suzuki reaction than Pd catalyst. The as-prepared catalyst displayed remarkable activity toward challenging substrates such as heteroaryl halides and ortho-substituted aryl halides as well as aryl chlorides using low Pd loading in good yields. Since the catalyst exhibits extremely low solubility in organic solvent, the product can be simply extracted with ethyl acetate while the catalyst remained in the aqueous phase. The catalyst can be simply and efficiently used for ten consecutive runs without significant decrease in activity.
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      PubDate: 2015-08-21T15:04:50Z
       
  • Modified manganese oxide octahedral molecular sieves M′-OMS-2
           (M′=Co,Ce,Cu) as catalysts in post plasma-catalysis for acetaldehyde
           degradation
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Yizhuo Li, Zeyun Fan, Jianwei Shi, Zhenyan Liu, Jiwen Zhou, Wenfeng Shangguan
      Metal ions-modified cryptomelane-type manganese oxide octahedral molecular sieves M′-OMS-2 (M′=Co,Ce,Cu) were synthesized and characterized by XRD, BET, EDS, ICP, TEM, XPS, FTIR, H2-TPR in this work. The obtained materials were supported on Al2O3 pellets and investigated for acetaldehyde degradation in a post plasma-catalysis system. The results showed that the introduction of M′-OMS-2/Al2O3 catalysts improved acetaldehyde removal efficiency and inhibited ozone formation of plasma significantly, while the intermediates such as acetic acid, amine and nitromethane were suppressed. Co-OMS-2/Al2O3 exhibited the best catalytic activity to combine with plasma among all the prepared catalysts. The excellent activity is ascribed to the redox property, oxygen vacancies, oxygen mobility and surface area of catalyst. It can be inferred that, ozone formed in plasma was catalytically dissociated into active oxygen species by metal ions in M′-OMS-2 catalysts and contributed to acetaldehyde oxidation and intermediates removal.
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      PubDate: 2015-08-21T15:04:50Z
       
  • Effect of the adsorbent/catalyst preparation method and plasma reactor
           configuration on the removal of dilute ethylene from air stream
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Quang Hung Trinh, Young Sun Mok
      13X zeolite-supported Ag was employed as the dual-functional adsorbent/catalyst for the plasma-catalytic abatement of dilute ethylene. The adsorbent/catalyst prepared by ion exchange (Ag-EX/13X) exhibited better adsorption capability than the parent 13X and Ag-IM/13X prepared by the impregnation method. The oxidative transformation of the adsorbed ethylene was then performed by using three different reactor configurations such as one-stage (i.e., adsorbent/catalyst in direct contact with plasma), two-stage (i.e., adsorbent/catalyst located downstream of the plasma region), and the combination of the two (hybrid). The oxidation of the adsorbed ethylene to CO2 in the two-stage configuration can be explained by the diffusion of ozone into zeolite micro-pores, which was, however, much slower than in the one-stage and hybrid configurations. When compared at an identical applied voltage of 20kV (inlet ethylene: 200ppm; adsorption time: 100min; plasma oxidation time: 20min), the mineralization efficiency of the hybrid reactor was greater than the sum of those of one- and two-stage reactors, i.e., 63, 42, and 10%, respectively. Using the hybrid configuration, ozone and other reactive species were more effectively produced, thereby shortening the oxidation time of ethylene and therefore achieving a higher energy efficiency which was evaluated to be ca. 2.4g (kWh)−1.
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      PubDate: 2015-08-21T15:04:50Z
       
  • Radio-frequency H2 plasma treatment of AuPd/TiO2 catalyst for selective
           hydrogenation of acetylene in excess ethylene
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Shuo Zhang, Chu-Ying Chen, Ben W.-L. Jang, Ai-Min Zhu
      Supported Au catalysts modified by addition of small amount of Pd (Au/Pd atomic ratio=14) are prepared by deposition-precipitation with NH3 (DP-NH3) followed by impregnation methods on TiO2. Low-pressure radio-frequency (RF) H2 plasma treatment has been applied to AuPd/TiO2 for the selective hydrogenation of acetylene. Compared with conventional thermal reduction (AuPd-250), the acetylene conversion over plasma-treated catalyst (AuPd-P) has been improved significantly while the ethylene selectivity shows the opposite trend. With additional thermal reduction on the plasma-treated catalyst (AuPd-P250), the acetylene conversion is decreased and the ethylene selectivity is increased, however, they are still in between those of AuPd-P and AuPd-250. To understand the plasma effect, the catalysts are characterized by XPS, in situ FTIR spectra of CO adsorption and pulse H2 chemisorption techniques. The high acetylene conversion of AuPd-P is ascribed to its large amount of surface Pd sites for acetylene adsorption, while its poor ethylene selectivity is due to the formation of contiguous Pd ensembles, which will cause the over hydrogenation of acetylene. The DTG results of the used catalyst indicate that the formation of green oil on or in the vicinity of Pd is suppressed over AuPd-P and AuPd-P250, and that is the reason why the plasma-treated samples are less deactivated than AuPd-250.
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      PubDate: 2015-08-21T15:04:50Z
       
  • Controlled surface properties of Au/ZSM5 catalysts and their effects in
           the selective oxidation of ethanol
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Hong Chen, Xinli Jia, Yongdan Li, Changjun Liu, Yanhui Yang
      The catalytic activity of gold supported on ZSM5 (Au/ZSM5) was investigated for the selective oxidation of ethanol in the presence of excess oxygen. Au/ZSM5 catalyst pretreated by nonthermal O2 plasma method showed the best oxidative activity compared to low-temperature calcination in air and high-temperature reduction in hydrogen atmosphere. Results from microscopy and X-ray diffraction characterizations proved that plasma pretreatment afforded a small Au particle size and a uniform dispersion of Au nanoparticles on ZSM5 surfaces. Characterization results further demonstrated that the residual ammonia adsorbed on ZSM5 surfaces during the precipitation can be oxidized to nitrate ions by nonthermal O2 plasma treatment, while it converted to NO+ by low-temperature oxygen calcination and was completely removed by high-temperature hydrogen reduction. Dissimilar surface/interface properties caused the tremendously different interaction between gold nanoparticles and zeolite support, and consequently the catalytic performances in ethanol oxidation. In particular, under the nonthermal O2 plasma pretreatment, the formed NO3 − species lowered the acidity of ZSM5 surfaces as well as anchored the Au nanoparticles, resulting in nearly 100% selectivity toward selective oxidation instead of acid-catalyzed reactions even under high reaction temperature.
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      PubDate: 2015-08-21T15:04:50Z
       
  • Enhanced activity for CO oxidation over Pd/Al2O3 catalysts prepared by
           atmospheric-pressure cold plasma
    • Abstract: Publication date: 1 November 2015
      Source:Catalysis Today, Volume 256, Part 1
      Author(s): Weijie Xu, Zhibin Zhan, Lanbo Di, Xiuling Zhang
      Atmospheric-pressure dielectric barrier discharge (DBD) cold plasma was employed to prepare Pd/Al2O3 catalysts by simple incipient wetness impregnation using Pd(NO3)2 and PdCl2 as precursors, respectively. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) and N2 adsorption–desorption measurement were used to characterize the Pd/Al2O3 catalysts. CO catalytic oxidation reaction was adopted to investigate the activity of the catalysts. The activity for the Pd/Al2O3 samples prepared by cold plasma using the same Pd precursor was higher than that prepared by thermal reduction method, which indicated that cold plasma is an efficient method for preparing high-performance Pd/Al2O3 catalysts. The results also showed that the Pd/Al2O3 catalysts prepared using Pd(NO3)2 as precursor possess smaller size of Pd nanoparticles, and most of the Pd nanoparticles were distributed on the surface of the Al2O3 support. In addition, a certain amount of chemisorbed oxygen species were detected on the surface of Al2O3 support due to the oxygen-containing Pd precursor. Therefore, they exhibited significantly enhanced activity for CO oxidation than that prepared using PdCl2 as Pd precursor. Atmospheric-pressure DBD cold plasma is a fast and facile method (just 6-min reduction) for fabricating high-performance Pd/Al2O3 catalysts using Pd(NO3)2 as Pd precursor.
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      PubDate: 2015-08-21T15:04:50Z
       
  • Green bioprocesses in sponge-like ionic liquids
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Pedro Lozano, Juana M. Bernal, Celia Gómez, Eduardo García-Verdugo, M. Isabel Burguete, Gregorio Sánchez, Michel Vaultier, Santiago V. Luis
      Ionic liquids (ILs) are a new class of liquid solvent, whose use has led to a green chemical revolution because of their unique array of physico-chemical properties, headed by their negligible vapour pressure and their exceptional ability to stabilize biocatalysts. Hydrophobic ILs based on cations with long alkyl side-chains, e.g. N,N,N,N-hexadecyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2]), are temperature switchable ionic liquid/solid phases that behave as sponge-like systems (sponge-like ionic liquid, SLILs). Based on this new property, SLILs have been used to develop straightforward and clean approaches for producing nearly pure synthetic compounds with added value (e.g. geranyl acetate, anisyl acetate, methyl oleate, etc.) in two steps: an enzymatic synthetic step as liquid phase, and then a product separation step involving simple centrifugation as a solid phase.
      Graphical abstract image

      PubDate: 2015-07-23T17:42:23Z
       
  • Preface
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Pedro Lozano, Santiago V. Luis, Eduardo Garcia-Verdugo, Roberto Fernández-Lafuente



      PubDate: 2015-07-23T17:42:23Z
       
  • Enzymatic synthesis of butyl acetate in a packed bed reactor under liquid
           and supercritical conditions
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): J. Escandell, D.J. Wurm, M.P. Belleville, J. Sanchez, M. Harasek, D. Paolucci-Jeanjean
      In this work we studied the synthesis of butyl acetate in an enzymatic packed bed reactor using lipase B, from Candida antarctica, immobilized by simple physical adsorption on porous pellets. The enzymatic reaction was carried out in two different solvents: a conventional organic solvent (n-hexane) and a green solvent (supercritical carbon dioxide). The highest ester productivity in hexane ( 119   μ mol min − 1   g pellets − 1 ) was reached at 323K, whereas in supercritical CO2, a maximum productivity of 501   μ mol min − 1   g pellets − 1 was achieved at 333K and under 12MPa. The environmental impacts of each process were estimated by means of the E-factor (mass ratio of amount of waste produced divided by amount of desired product) and the values obtained under the previous conditions were 28.7 and 12.0 respectively. Results show that replacing hexane by supercritical CO2 in a continuous process increases ester productivity and reduces environmental impact, thus allowing making a more environmentally friendly process.
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      PubDate: 2015-07-23T17:42:23Z
       
  • Synthesis of cetyl ricinoleate catalyzed by immobilized Lipozyme®
           CalB lipase in a solvent-free system
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): M.C. Montiel, M. Serrano, M.F. Máximo, M. Gómez, S. Ortega-Requena, J. Bastida
      A green process has been performed for the synthesis of the emollient ester cetyl ricinoleate with a new immobilized derivative of Candida antarctica lipase B, which has been prepared by physical adsorption of Lipozyme® CalB L on a macroporous anionic exchange resin (Lewatit® MonoPlus MP 64). An immobilized CalB lipase with protein content over 30mg/g has been obtained and it has been successfully used as biocatalyst to produce cetyl ricinoleate from esterification of ricinoleic acid with cetyl alcohol. Influence of amount of biocatalyst and temperature was studied in the open-air reactor, and optimal values could be fixed in 2mg and 70°C, respectively. Biocatalyst storage stability study was developed in this reactor and it was showed the high storage stability of the immobilized derivative, because it keeps 100% of its enzymatic activity after eight months. Studies of recovery and reuse of the immobilized derivative were performed in the vacuum reactor, and it was proved the possibility of using the same biocatalyst in three consecutive reaction cycles without apparent loss of activity. Finally, the characterization of the cetyl ricinoleate obtained in the vacuum reactor demonstrated that the product obtained after only 3 or 4h of reaction meets manufacturers’ specifications.
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      PubDate: 2015-07-23T17:42:23Z
       
  • Lipase-mediated dynamic kinetic resolution (DKR) of secondary alcohols in
           the presence of zeolite using an ionic liquid solvent system
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Ken-ichi Shimomura, Hiroyuki Harami, Yui Matsubara, Toshiki Nokami, Naonobu Katada, Toshiyuki Itoh
      Transition metal free dynamic kinetic resolution (DKR) of 1-phenyethanol and 2,3-dihydro-1H-inden-1-ol has been accomplished by the combination of Candida antarctica lipase (CAL-B) and zeolite using vinyl octanoate or p-chlorophenyl pentanoate as acyl donor in a mixed solvent system of ionic liquid and hexane in the presence of 1.0eq. of water. Duplicated use of the catalysts has also been demonstrated in the DKR of 2,3-dihydro-1H-inden-1-ol using this reaction system.
      Graphical abstract image

      PubDate: 2015-07-23T17:42:23Z
       
  • Xylitol production from cashew apple bagasse by Kluyveromyces marxianus
           CCA510
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Tiago Lima de Albuquerque, Sandy Danielle Luncindo Gomes, José Edvan Marques Jr., Ivanildo José da Silva Jr., Maria Valderez Ponte Rocha
      The production of xylitol, a polyol with high employability in the food and pharmaceutical industry, from cashew apple bagasse hydrolysate (CABH) by a new strain of Kluyveromyces marxianus was studied. Initially, the use of activated charcoal in the detoxification of hydrolysates from CABH was evaluated. Then, the influence of the supplementation of CABH with various nitrogen sources was studied. The activated charcoal reduced the concentration of acid and phenolic compounds. K. marxianus CCA510 was able to produce xylitol using CABH, with the highest yield of 0.36gg−1 and maximum concentration of 12.73gL−1. When it was added urea in the medium the highest xylitol yield was observed, reaching 0.50gg−1, showing that substance as nitrogen source improved the xylitol production. The cashew apple bagasse hydrolysate is a potential medium for biotechnological production of xylitol and detoxification treatments can be employed to reduce potential toxic compounds present in the medium without significant loss of sugars.
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      PubDate: 2015-07-23T17:42:23Z
       
  • Use of Lecitase-Ultra immobilized on styrene-divinylbenzene beads as
           catalyst of esterification reactions: Effects of ultrasounds
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Joana S. Alves, Cristina Garcia-Galan, Daiane Danelli, Natália Paludo, Oveimar Barbosa, Rafael C. Rodrigues, Roberto Fernandez-Lafuente
      In this work it was evaluated for the first time, the ester synthesis catalyzed by the phospholipase Lecitase-Ultra immobilized styrene-divinylbenzene beads (MCI-Lecitase), comparing the mechanical stirring and the ultrasonic energy. It was studied the specificity of the enzyme using carboxylic acids from C4 to C18, as well as the effects of alcohol chain, organic solvents, biocatalyst content, reaction temperature and substrate concentration. Caprylic and myristic acids were those with the highest reaction rates and yields, using ethanol as substrate. The shorter the alcohol chain, the higher the enzyme activity. Regarding the secondary alcohols, while MCI-Lecitase had no activity versus isopropanol, using 2-pentanol the activity was similar to that with 1-pentanol. Comparing the agitation systems, MCI-Lecitase presented an initial reaction rate more than 2-times higher in the ultrasound-assisted reaction than under traditional mechanical stirring. Moreover, under ultrasonic energy the maximum rate was achieved using 0.5M of substrates, while under mechanical stirring the maximum enzyme activity was reached at 0.3M of substrates. Concerning the operational stability, MCI-Lecitase was quite unstable, losing its activity after 6 reaction cycles. By adding molecular sieves in the reaction medium, MCI-Lecitase retained 30% of its initial activity after 6 cycles.
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      PubDate: 2015-07-23T17:42:23Z
       
  • Asymmetric hydrolysis of dimethyl-3-phenylglutarate in sequential batch
           reactor operation catalyzed by immobilized Geobacillus thermocatenulatus
           lipase
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Nadia Guajardo, Claudia Bernal, Lorena Wilson, Zaida Cabrera
      The main goal of this work was to study the stereoselective behavior of immobilized Geobacillus thermocatenulatus lipase (BTL2) in a sequential batch reactor using the partial and asymmetric hydrolysis of dimethyl-3 phenylglutarate (DMFG) as a model reaction. To reach this goal, BTL2 lipase was immobilized on Sepharose and silica supports with cyanogen bromide and octyl groups (monofunctional supports) and undecanol-glyoxyl and octyl-epoxides groups (heterofunctional supports), to determine the effect of the enzyme orientation during the immobilization process on their catalytic properties. In the hydrolysis of DMFG, the biocatalyst obtained with undecanol-glyoxyl Sepharose proved to be the most stereolective with an enantiomeric excess (e.e.) value of 90% in aqueous media. This behavior can be attributed to differences in the orientation of the lipase on the support. In sequential batch reactor operation, the e.e. remained constant in the first two batches; however, from the third batch on the e.e. decreased slightly maybe due to a change in the conformation of the enzyme at the reaction conditions. Finally, the high purity S-methyl-3-phenyl glutarate produced in sequential batch reactor operation shows that the biocatalyst can be reused at least twice without losing stereoselectivity, favoring a reduction in the process cost.
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      PubDate: 2015-07-23T17:42:23Z
       
  • Kinetic resolution of esters from secondary and tertiary benzylic
           propargylic alcohols by an improved esterase-variant from Bacillus sp.
           BP-7
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Amanda Fillat, Pedro Romea, F.I. Javier Pastor, Fèlix Urpí, Pilar Diaz
      We described in a recent work the rational improvement of an esterase from Bacillus sp. BP7 aimed at investigating the efficiency of several esterase variants for enantiomeric resolution of acetate esters of tertiary alcohols. Variant EstBP7-AGA, bearing two aminoacidic changes in the oxyanion hole, showed an excellent E >100 enantioselectivity value towards a complex tertiary alcohol acetate (2-(4-pyridyl)-3-butyn-2-yl acetate) at low reaction temperature (4°C). We here go further in the investigation of such esterase variant by analyzing the kinetic resolution of benzylic propargylic esters to prove that this enzyme is a powerful tool to obtain enantiomerically pure tertiary as well as secondary alcohols, provided that the structural integrity of the parent benzylic propargylic ester is maintained. Understanding the mode of action and interaction of such esterase variant with the assayed substrates will allow production of interesting pharmaceutical building blocks.
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      PubDate: 2015-07-23T17:42:23Z
       
  • Production of a biosurfactant by Bacillus subtilis ICA56 aiming
           bioremediation of impacted soils
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Ítalo Waldimiro Lima de França, Andrea Parente Lima, João Alexandre Monteiro Lemos, Celina Gentil Farias Lemos, Vania Maria Maciel Melo, Hosiberto Batista de Sant’ana, Luciana Rocha Barros Gonçalves
      This work aimed to study the production of a biosurfactant by a new strain of Bacillus subtilis ICA56 isolated from a Brazilian mangrove and to evaluate its functional properties and applicability for bioremediation. The use of agro-industrial wastes (glycerol, sunflower oil, cheese whey and cashew apple juice) as alternative substrates for biosurfactant production was tested as this may lead to a reduction in the cost of the bioprocess. Glycerol was the best carbon source yielding 1290mgL−1 of crude biosurfactant. The critical micellar concentration of the crude biosurfactant produced by ICA56 was 25mgL−1 and, at this concentration, it was able to reduce the surface tension of the water from 72 to 30mNm−1 and to reduce the interfacial tension on a water/gasoline system from 15 to 3mNm−1. Furthermore, the crude biosurfactant retained its tensoative properties in a broad range of pH, temperature and salinity and it was not toxic to Artemia salina. In this work, model experiments were conducted to simulate the removal of hydrocarbons and heavy metals from contaminated environmental systems in the laboratory by the crude biosurfactant produced by ICA56. Results showed that it was very efficient, highlighting its potential for bioremediation.
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      PubDate: 2015-07-23T17:42:23Z
       
  • IFC - Editorial Board
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255




      PubDate: 2015-07-23T17:42:23Z
       
  • Contents list
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255




      PubDate: 2015-07-23T17:42:23Z
       
  • Advanced nanostructured catalysts for hydroboration
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Virginie Liautard, Oana Pascu, Cyril Aymonier, Mathieu Pucheault
      Metal nanocrystals have been prepared in onium salts using supercritical carbon dioxide assisted synthesis. During the process, metal salts precursors are reduced by H2 in an organic solvent free media, the onium salts allowing both the stabilization of the nanostructured material and the preparation of an air and moisture stable powder made of embedded metal nanocrystals. Those catalysts proved to be highly effective in the hydroboration of alkyne process.
      Graphical abstract image

      PubDate: 2015-07-23T17:42:23Z
       
  • Microwaves under pressure for the continuous production of quinoline from
           glycerol
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): H. Saggadi, I. Polaert, D. Luart, C. Len, L. Estel
      Microwave heating is an interesting technology for chemical engineering, since it can provide effective volumetric heating of the reaction medium and reduce energy costs. Many commercially available laboratory-scale microwave reactors have already been used to carry out chemical reactions on a small scale (a few milliliters), and at high temperatures and pressures. Some research has been undertaken to scale-up microwave processes and make them suitable for a larger scale production. Indeed, combining wave propagation through the walls of a reactor with resistance toward high pressure and temperature as well, is not an easy task. For these reasons, this work focuses on the development of a pilot scale microwave apparatus used for the heating of larger reaction volumes under pressure, and under controlled conditions. The specially designed microwave apparatus allows chemical reactions in batch or continuous mode. The applicator operates in single mode enabling a uniform electromagnetic field, and well controlled operating conditions. The main advantage of the setup is the quite large reactor volume that permits either relatively long residence times or relatively high mass flowrates (up to 1kg/h). The developed microwave apparatus was then used for quinoline synthesis from glycerol via a modified Skraup reaction. The major advantage of our system is the ability to carry out continuous chemical synthesis, at a large pilot scale, and high temperatures (200–220°C), while ensuring a better control of the pressure (max. 19bar) through the control of the power absorbed by the reaction medium.
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      PubDate: 2015-07-23T17:42:23Z
       
  • Direct thermo-catalytic transformation of pine wood into low oxygenated
           fuel: Influence of the support
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Anthony Garron, Walid Al Maksoud, Cherif Larabi, Philippe Arquillière, Kai C. Szeto, Jean-Jacques Walter, Catherine C. Santini
      The direct catalytic thermo-catalytic transformation of wood in presence of molecular hydrogen has been demonstrated. The resulting organic liquid consists of saturated alkanes and aromatics and was obtained with a yield up to 30wt.%. Importantly, the oxygen content is about 3wt.% (<5wt.% required for bio-fuel formulation) and has a Higher Heating Value of 41MJkg−1 which is very close to standard diesel (44MJkg−1) used in automotive fuel. The catalysts comprise multi-functional Cu–Ru supported on Cs exchanged heteropolyacid (H3PW12O40 and H3PMo12O40), featuring depolymerisation, deoxygenation and hydrogenation in a single batch reactor. Current results present an alternative approach to convert highly oxygenated lignocellulosic biomass to a low oxygenated organic liquid suitable as additives in biofuels, in one step and one reactor.
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      PubDate: 2015-07-23T17:42:23Z
       
  • Selective transformation of fructose and high fructose content biomass
           into lactic acid in supercritical water
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Danilo A. Cantero, Luis Vaquerizo, Celia Martinez, M. Dolores Bermejo, M. José Cocero
      The reactions of fructose in sub- and supercritical water were analyzed changing the chemical properties of the reaction medium (Kw, ɛ, pH and free radical kidnapers). The reactions were performed in a continuous reactor at 260°C, 330°C and 400°C, at 23MPa and 27MPa using water as reaction medium. The pH of the medium was modified using oxalic acid and sodium hydroxide. Also, scavengers (TEMPO and BHT) were tested in order to determine its influences in the radical reactions. The main product of fructose hydrolysis in supercritical water was pyruvaldehyde (>80%, w·w−1) at 400°C and 23MPa with a reaction time of 0.7s. Furthermore, the reactions of fructose were analyzed in combination with glucose. It was determined that different retro-aldol condensation products can be obtained depending on the starting material. Fructose produced mainly C-3 molecules (pyruvaldehyde) and glucose produced mainly C-2 molecules (glycolaldehyde). The isomerization of fructose to glucose was negligible and so was the production of C-2 when the starting material was fructose. The yield of 5-HMF was negligible when the starting material was glucose. Three different biomass enriched in fructose (sugar cane molasses, beet molasses and inulin) were tested as starting material for the hydrolysis process. It was determined that lactic acid (50%, w·w−1) was the main product of molasses and inulin hydrolysis in a supercritical water medium modified with basic catalysts.
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      PubDate: 2015-07-23T17:42:23Z
       
  • Solubility of greenhouse and acid gases on the [C4mim][MeSO4] ionic liquid
           for gas separation and CO2 conversion
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Fèlix Llovell, Mariana B. Oliveira, João A.P. Coutinho, Lourdes F. Vega
      Ionic liquids (ILs) are an exciting class of compounds of high interest from a technological point of view. One of the applications that is raising more interest is their possible use as solvents to carry out the conversion of CO2 into more valuable compounds. Theoretical approaches provide an attractive option to screen ILs properties and give quick answers to guide the experiments, becoming a crucial tool for process design. This work illustrates a practical example based on the solubility of greenhouse and acid gases on the butylmethylimidazolium methylsulfate [C4mim][MeSO4] IL, in order to study its feasibility for gas separation and conversion. A simple but reliable molecular model is presented for the ionic liquid based on structural information and molecular simulations, and coarse-grained models are used to model the different gases. The absorption of relevant gases for the separation/conversion process (CO2, CH4, CO, H2, SO2, H2S) in [C4mim][MeSO4] is modeled and compared with experimental data using a minimum amount of binary data. From this information, the ternary diagrams of [C4mim][MeSO4] with CO2 and the acid gases SO2 and H2S are predicted, and the selectivity of CO2 by respect all the gases is evaluated, with particular attention to the contaminants above mentioned.
      Graphical abstract image

      PubDate: 2015-07-23T17:42:23Z
       
  • Gold nanoparticles immobilized onto supported ionic liquid-like phases for
           microwave phenylethanol oxidation in water
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Julian Restrepo, Pedro Lozano, M. Isabel Burguete, Eduardo García-Verdugo, Santiago V. Luis
      Advanced crosslinked polymeric materials based on poly(ionic liquid)s, also named supported ionic liquid-like phases (SILLPs) combine some unique characteristics of ionic liquids with the general property profile of macromolecular architectures, and present huge potential in energy-/environment-/catalysis-oriented applications, in the development of “smart” dispersants and stabilizers, etc. One of these relevant applications is highlighted by the present results that involve their use for the preparation and stabilization of different type of catalytic units, in particular metal nanoparticles (MeNPs) in order to develop greener catalytic processes. Different kinds of stable AuNPs can be prepared from SILLPs-related polymeric materials and have been used for the efficient oxidation of phenyl ethanol, under aerobic conditions, using H2O2 as the oxidant and under microwave irradiation.
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      PubDate: 2015-07-23T17:42:23Z
       
  • Oxodiperoxomolybdenum complex immobilized onto ionic liquid modified
           SBA-15 as an effective catalysis for sulfide oxidation to sulfoxides using
           hydrogen peroxide
    • Abstract: Publication date: 15 October 2015
      Source:Catalysis Today, Volume 255
      Author(s): Carlos J. Carrasco, Francisco Montilla, Luis Bobadilla, Svetlana Ivanova, José Antonio Odriozola, Agustín Galindo
      A supported ionic-liquid-phase (SILP) was prepared by the reaction of 1-methyl-3-(3-(triethoxysilyl)propyl)-1H-imidazol-3-ium chloride with a mesoporous SBA-15 silica and then an oxodiperoxomolybdenum complex was immobilized onto the obtained SILP. The resulting material, identified as SBA-15+ImCl+MoO5, was characterized by solid state NMR (1H, 13C and 29Si), and their textural and thermogravimetric properties were determined. The SBA-15+ImCl+MoO5 material was investigated as catalyst for the oxidation of methylphenylsulfide, as model reaction, with aqueous hydrogen peroxide as oxidant at room temperature. The presence of the molybdenum species was crucial for achieving good conversions and methanol was selected as the best solvent (conversion of 95% and selectivity toward sulfoxide 98%). The optimized reaction conditions were applied for the oxidation of several selected sulfides. In general, good catalytic activity and selectivity to sulfoxide were obtained and, remarkably, the selectivity toward sulfoxide is higher than those observed in the study of the same process carried out in [C4min][PF6] (C4mim=1–butyl-3-methylimidazolium) and catalyzed by a molecular molybdenum complex, under the same reaction conditions. The importance of the IL-functionalization in the SBA-15 material was evidenced by recycling experiments. The SBA-15+ImCl+MoO5 catalyst was used for the sulfoxidation of the methylphenylsulfide substrate for ten reaction cycles without a significant change in conversion, selectivity to sulfoxide and molybdenum content.
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      PubDate: 2015-07-23T17:42:23Z
       
 
 
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