scholarly journals Catalytic Behaviour of Mesoporous Cobalt-Aluminum Oxides for CO Oxidation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ankur Bordoloi ◽  
Miguel Sanchez ◽  
Heshmat Noei ◽  
Stefan Kaluza ◽  
Dennis Großmann ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Self Assembly ◽  
Mixed Oxides ◽  
High Specific Surface Area ◽  
Alumina Matrix ◽  
Spinel Type ◽  
Aluminum Oxides ◽  
Cobalt Ions ◽  
Ordered Mesoporous Materials ◽  
Calcination Temperatures

Ordered mesoporous materials are promising catalyst supports due to their uniform pore size distribution, high specific surface area and pore volume, tunable pore sizes, and long-range ordering of the pore packing. The evaporation-induced self-assembly (EISA) process was applied to synthesize mesoporous mixed oxides, which consist of cobalt ions highly dispersed in an alumina matrix. The characterization of the mesoporous mixed cobalt-aluminum oxides with cobalt loadings in the range from 5 to 15 wt% and calcination temperatures of 673, 973, and 1073 K indicates that Co2+ is homogeneously distributed in the mesoporous alumina matrix. As a function of the Co loading, different phases are present comprising poorly crystalline alumina and mixed cobalt aluminum oxides of the spinel type. The mixed cobalt-aluminum oxides were applied as catalysts in CO oxidation and turned out to be highly active.

Ordered Mesoporous Materials from Metal Nanoparticle-Block Copolymer Self-Assembly

Science ◽  
2008 ◽  
Vol 320 (5884) ◽  
pp. 1748-1752 ◽  
Author(s):  
S. C. Warren ◽  
L. C. Messina ◽  
L. S. Slaughter ◽  
M. Kamperman ◽  
Q. Zhou ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Mesoporous Materials ◽  
Self Assembly ◽  
Metal Nanoparticle ◽  
Ordered Mesoporous Materials ◽  
Ordered Mesoporous

scholarly journals Simultaneous Catalytic Oxidation of a Lean Mixture of CO-CH4 over Spinel Type Cobalt Based Oxides

2020 ◽  
Vol 15 (2) ◽  
pp. 490-500
Author(s):  
Neha Neha ◽  
Ram Prasad ◽  
Satya Vir Singh
Keyword(s):  
Mixed Oxides ◽  
Structural Disorder ◽  
Catalytic Performance ◽  
Molar Ratio ◽  
Total Oxidation ◽  
Spinel Type ◽  
Molar Ratios ◽  
Long Term Stability ◽  
Nickel Cobalt ◽  
Temperature Programmed

A series of nickel-cobalt bimetal oxides in varying molar ratios and its single metal oxides were synthesized by reactive calcination of coprecipitated basic-carbonates. Several characterization techniques, such as: Bruneuer Emmett Teller (BET), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infra Red (FTIR), and Hydrogen Temperature Programmed Reduction (H2-TPR), were performed over the oxides. Activities of oxides were evaluated in methane total oxidation in the presence or the absence of CO. The best catalytic performance was observed over NiCo catalyst with a Ni/Co molar ratio of 1:1, and the complete conversion of CO-CH4 mixture was achieved at 390 °C. Moreover, the presence of carbon monoxide improves CH4 total oxidation over nickel-cobalt mixed oxides. Structural analysis reveals that the insertion of nickel into the spinel lattice of cobalt oxide causes the structural disorder, which probably caused the increase of the amount of octahedrally coordinated divalent nickel cations that are responsible for catalytic activity. Stability of the best-performed catalyst has been tested in the two conditions, showing remarkable long-term stability and thermal stability, however, showed deactivation after thermally ageing at 700 °C. Copyright © 2020 BCREC Group. All rights reserved 

scholarly journals Photocatalytic Improvement under Visible Light inTiO2Nanoparticles by Carbon Nanotube Incorporation

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mathana Wongaree ◽  
Siriluk Chiarakorn ◽  
Surawut Chuangchote
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Sol Gel ◽  
Multiwall Carbon Nanotubes ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Calcination Temperatures ◽  
Photocatalytic Activities ◽  
Multiwall Carbon

Photocatalytic activity ofTiO2nanoparticles was successfully enhanced by addition of multiwall carbon nanotubes (MWCNT) to make CNT/TiO2nanocomposites by sol-gel method at ambient temperature. CNT treated by HNO3 : H2SO4treatment (1 : 3 v/v) was mixed withTiO2nanoparticles at various molar ratios and calcination temperatures. The optimal molar ratio of CNT : TiO2was found at 0.05 : 1 by weight. The optimal calcination condition was 400°C for 3 h. From the results, the photocatalytic activities of CNT/TiO2nanocomposites were determined by the decolorization of 1 × 10−5 M methylene blue (MB) under visible light. CNT/TiO2nanocomposites could enhance the photocatalytic activity and showed faster for the degradation of MB with only 90 min. The degradation efficiency of the MB solution with CNT/TiO2nanocomposite achieved 70% which was higher than that with pristineTiO2(22%). This could be explained that CNT preventsTiO2from its agglomeration which could further enhance electron transfer in the composites. In addition, CNT/TiO2nanocomposites had high specific surface area (202 m2/g) which is very promising for utilization as a photocatalyst for environmental applications.

scholarly journals Mixed-Oxide Catalysts with Spinel Structure for the Valorization of Biomass: The Chemical-Loop Reforming of Bioethanol

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 332 ◽  
Author(s):  
Olena Vozniuk ◽  
Tommaso Tabanelli ◽  
Nathalie Tanchoux ◽  
Jean-Marc Millet ◽  
Stefania Albonetti ◽  
...  
Keyword(s):  
Solid State ◽  
Spinel Structure ◽  
Mixed Oxides ◽  
Building Blocks ◽  
Short Review ◽  
Solid State Chemistry ◽  
Spinel Type ◽  
Mixed Oxide Catalysts ◽  
Versatile Tool ◽  
Review Reports

This short review reports on spinel-type mixed oxides as catalysts for the transformation of biomass-derived building blocks into chemicals and fuel additives. After an overview of the various methods reported in the literature for the synthesis of mixed oxides with spinel structure, the use of this class of materials for the chemical-loop reforming of bioalcohols is reviewed in detail. This reaction is aimed at the production of H2 with intrinsic separation of C-containing products, but also is a very versatile tool for investigating the solid-state chemistry of spinels.

Physicochemical characterization and catalytic CO oxidation performance of nanocrystalline Ce–Fe mixed oxides

RSC Advances ◽  
2014 ◽  
Vol 4 (22) ◽  
pp. 11322-11330 ◽  
Author(s):  
Putla Sudarsanam ◽  
Baithy Mallesham ◽  
D. Naga Durgasri ◽  
Benjaram M. Reddy
Keyword(s):  
Co Oxidation ◽  
Oxygen Vacancies ◽  
Lattice Strain ◽  
Mixed Oxides ◽  
Physicochemical Characterization ◽  
Oxidation Activity ◽  
Catalytic Co Oxidation ◽  
Nano Oxide ◽  
Oxidation Performance

Fe-doped CeO2 nano-oxide exhibited superior CO oxidation activity compared to pristine CeO2 due to its facile reducible nature, enhanced lattice strain, and ample oxygen vacancies.

Transformation of Methane into Synthesis Gas Using the Redox Property of Pr-Zr Mixed Oxides: Effect of Calcination Temperature

2013 ◽  
Vol 724-725 ◽  
pp. 1187-1191
Author(s):  
Yong Gang Wei ◽  
Yun Peng Du ◽  
Kong Zhai Li ◽  
Xing Zhu ◽  
Hua Wang
Keyword(s):  
Calcination Temperature ◽  
Synthesis Gas ◽  
Mixed Oxides ◽  
Structural Evolution ◽  
Temperature Stability ◽  
Phase Segregation ◽  
Oxygen Carriers ◽  
High Temperature Stability ◽  
Calcination Temperatures ◽  
Co Precipitation

Pr-Zr mixed oxides prepared by co-precipitation were used as oxygen carriers for converting methane into synthesis gas through gas-solid reactions. The structural evolution and reducibility of Pr-Zr oxygen carriers with calcination temperatures from 600 to 1200°C were investigated by XRD and TPR techniques and correlated to their activity for methane selective oxidation. The Pr-Zr mixed oxides calcined at 600-800°C show outstanding thermostability, and higher calcination temperatures result in phase segregation. Pr0.7Zr0.3O2-δ possesses high temperature stability(<900 °C) and the best appropriate calcination temperature is 800°C for methane gas-solid reaction.

scholarly journals Effect of the Preparation Method on the Physicochemical Properties and the CO Oxidation Performance of Nanostructured CeO2/TiO2 Oxides

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 847 ◽  
Author(s):  
Sofia Stefa ◽  
Maria Lykaki ◽  
Dimitrios Fragkoulis ◽  
Vasileios Binas ◽  
Pavlos K. Pandis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Co Oxidation ◽  
Rational Design ◽  
Mixed Oxides ◽  
Oxygen Storage ◽  
Precipitation Method ◽  
Stöber Method ◽  
X Ray ◽  
Oxidation Performance ◽  
The Stöber Method

Ceria-based mixed oxides have been widely studied in catalysis due to their unique surface and redox properties, with implications in numerous energy- and environmental-related applications. In this regard, the rational design of ceria-based composites by means of advanced synthetic routes has gained particular attention. In the present work, ceria–titania composites were synthesized by four different methods (precipitation, hydrothermal in one and two steps, Stöber) and their effect on the physicochemical characteristics and the CO oxidation performance was investigated. A thorough characterization study, including N2 adsorption-desorption, X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscopy (TEM) and H2 temperature-programmed reduction (H2-TPR) was performed. Ceria–titania samples prepared by the Stöber method, exhibited the optimum CO oxidation performance, followed by samples prepared by the hydrothermal method in one step, whereas the precipitation method led to almost inactive oxides. CeO2/TiO2 samples synthesized by the Stöber method display a rod-like morphology of ceria nanoparticles with a uniform distribution of TiO2, leading to enhanced reducibility and oxygen storage capacity (OSC). A linear relationship was disclosed among the catalytic performance of the samples prepared by different methods and the abundance of reducible oxygen species.

Copolymer Assisted Self-Assembly of Nanoporous Mixed Oxides for Reactive Adsorption Desulfurization

2016 ◽  
Vol 8 (11) ◽  
pp. 931-937
Author(s):  
Peng Bai ◽  
Rooh Ullah ◽  
Pengyun Liu ◽  
Bowen Liu ◽  
U. J. Etim ◽  
...  
Keyword(s):  
Self Assembly ◽  
Mixed Oxides ◽  
Reactive Adsorption ◽  
Adsorption Desulfurization
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