Formation of Gold Clusters on La–Ni Mixed Oxides and Its Catalytic Performance for Isomerization of Allylic Alcohols to Saturated Aldehydes

2014 ◽  
Vol 43 (8) ◽  
pp. 1368-1370 ◽  
Author(s):  
Tamao Ishida ◽  
Jun Aimoto ◽  
Akiyuki Hamasaki ◽  
Hironori Ohashi ◽  
Tetsuo Honma ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Catalytic Performance ◽  
Gold Clusters ◽  
Allylic Alcohols

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 Effect of the calcination temperature of cerium–zirconium mixed oxides on the structure and catalytic performance of WO3/CeZrO2 monolithic catalyst for selective catalytic reduction of NOx with NH3

RSC Advances ◽  
2017 ◽  
Vol 7 (39) ◽  
pp. 24177-24187 ◽  
Author(s):  
Haidi Xu ◽  
Mengmeng Sun ◽  
Shuang Liu ◽  
Yuanshan Li ◽  
Jianli Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Lewis Acid ◽  
Mixed Oxides ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Reduction Of Nox ◽  
Calcined Temperature

The calcined temperature of the carrier obviously affected SCR activity of catalysts, WO3/Ce0.68Zr0.32O2-500 showed the best low-temperature NH3-SCR activity due to its more Lewis acid sites and stronger redox property.

scholarly journals Highly Active Transition Metal-Promoted CuCeMgAlO Mixed Oxide Catalysts Obtained from Multicationic LDH Precursors for the Total Oxidation of Methane

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 613
Author(s):  
Hussein Mahdi S. Al-Aani ◽  
Mihaela M. Trandafir ◽  
Ioana Fechete ◽  
Lucia N. Leonat ◽  
Mihaela Badea ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transition Metal ◽  
Mixed Oxide ◽  
Mixed Oxides ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Total Oxidation ◽  
X Ray ◽  
Oxidation Of Methane ◽  
Al2o3 Catalyst

To improve the catalytic performance of an active layered double hydroxide (LDH)-derived CuCeMgAlO mixed oxide catalyst in the total oxidation of methane, it was promoted with different transition-metal cations. Thus, two series of multicationic mixed oxides were prepared by the thermal decomposition at 750 °C of their corresponding LDH precursors synthesized by coprecipitation at constant pH of 10 under ambient atmosphere. The first series of catalysts consisted of four M(3)CuCeMgAlO mixed oxides containing 3 at.% M (M = Mn, Fe, Co, Ni), 15 at.% Cu, 10 at.% Ce (at.% with respect to cations), and with Mg/Al atomic ratio fixed to 3. The second series consisted of four Co(x)CuCeMgAlO mixed oxides with x = 1, 3, 6, and 9 at.% Co, while keeping constant the Cu and Ce contents and the Mg/Al atomic ratio. All the mixed oxides were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) coupled with X-ray energy dispersion analysis (EDX), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption at −196 °C, temperature-programmed reduction under hydrogen (H2-TPR), and diffuse reflectance UV-VIS spectroscopy (DR UV-VIS), while thermogravimetric and differential thermal analyses (TG-DTG-DTA) together with XRD were used for the LDH precursors. The catalysts were evaluated in the total oxidation of methane, a test reaction for volatile organic compounds (VOC) abatement. Their catalytic performance was explained in correlation with their physicochemical properties and was compared with that of a reference Pd/Al2O3 catalyst. Among the mixed oxides studied, Co(3)CuCeMgAlO was found to be the most active catalyst, with a temperature corresponding to 50% methane conversion (T50) of 438 °C, which was only 19 °C higher than that of a reference Pd/Al2O3 catalyst. On the other hand, this T50 value was ca. 25 °C lower than that observed for the unpromoted CuCeMgAlO system, accounting for the improved performance of the Co-promoted catalyst, which also showed a good stability on stream.

scholarly journals Selective Oxidation of Glycerol Using 3% H2O2 Catalyzed by Supported Nano-Au Catalysts

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 505 ◽  
Author(s):  
Xiaoli Wang ◽  
Gongde Wu ◽  
Tongfa Jin ◽  
Jie Xu ◽  
Shihao Song
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Selective Oxidation ◽  
Mixed Oxide ◽  
Transition Metal Oxides ◽  
Mixed Oxides ◽  
Catalytic Performance ◽  
Glyceric Acid ◽  
Glycerol Conversion ◽  
Composition And Structure

A series of transition metal oxides or mixed oxides supported nano-Au catalysts were prepared for the selective oxidation of glycerol to glyceric acid using 3% H2O2. It was found that the composition and structure of supports significantly influenced the catalytic performance of catalysts. The mesoporous trimetal mixed oxide (CuNiAlO) supported nano-Au catalysts were more active in comparison with the others. In the present catalytic system, the highest glycerol conversion was 90.5%, while the selectivity of glyceric acid could reach 72%. Moreover, the catalytic performance remained after 11 times of reaction.

scholarly journals Effects of hydrogen peroxide co-precipitation and inert N2 atmosphere calcination on CeZrLaNd mixed oxides and the catalytic performance used on Pd supported three-way catalysts

RSC Advances ◽  
2019 ◽  
Vol 9 (14) ◽  
pp. 8081-8090 ◽  
Author(s):  
Meisheng Cui ◽  
Yongke Hou ◽  
Zhizhe Zhai ◽  
Qiang Zhong ◽  
Yongqi Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Particle Size ◽  
Mixed Oxides ◽  
Catalytic Performance ◽  
Peroxide Oxidation ◽  
N2 Atmosphere ◽  
Hydrogen Peroxide Oxidation ◽  
Co Precipitation

Hydrogen peroxide oxidation improves the grains growth. Inert N2 atmosphere calcination reduces the particle size and enlarges the pore channels.

scholarly journals Oxidative dehydrogenation of isobutane over supported V-Mo mixed oxides

2010 ◽  
Vol 75 (8) ◽  
pp. 1115-1124 ◽  
Author(s):  
Gheorghiţa Mitran ◽  
Ioan-Cezar Marcu ◽  
Adriana Urdă ◽  
Ioan Săndulescu
Keyword(s):  
Oxidative Dehydrogenation ◽  
Mixed Oxides ◽  
Catalytic Performance ◽  
Molybdenum Oxides ◽  
Impregnation Method ◽  
N2 Adsorption ◽  
Wet Impregnation ◽  
Vis Spectroscopy ◽  
Wet Impregnation Method ◽  
Oxidative Dehydrogenation Of Isobutane

Vanadium-molybdenum oxides supported on Al2O3, CeO2 and TiO2 were prepared by a ?wet? impregnation method, characterized using DRX, N2 adsorption, UV-Vis spectroscopy, electrical conductivity measurements and tested in the oxidative dehydrogenation of isobutane. The catalytic performance in the oxidative dehydrogenation of isobutane at 400-550?C depended on the nature of support and on the content of VMoO species on the support. The catalysts supported on alumina were more active and selective than those supported on ceria and titania.

Eu-Mn-Ti mixed oxides for the SCR of NOx with NH3: The effects of Eu-modification on catalytic performance and mechanism

2017 ◽  
Vol 167 ◽  
pp. 322-333 ◽  
Author(s):  
Chen Gao ◽  
Jian-Wen Shi ◽  
Zhaoyang Fan ◽  
Yanke Yu ◽  
Jinsheng Chen ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Catalytic Performance ◽  
Performance And Mechanism ◽  
Scr Of Nox
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