The Experts below are selected from a list of 5394 Experts worldwide ranked by ideXlab platform
Alan M. Lane - One of the best experts on this subject based on the ideXlab platform.
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Water-treated Rh/γ-Al_2O_3 catalyst for Methane Partial Oxidation
Applied Petrochemical Research, 2016Co-Authors: Alan M. LaneAbstract:A water treatment technique, using H_2 as a reducing agent in a wet environment, was applied to a conventional Rh/γ-Al_2O_3 catalyst. Both standard- and water-treated Rh/γ-Al_2O_3 catalysts were prepared and their catalytic performances were tested in Methane Partial Oxidation reaction. The water-treated Rh/γ-Al_2O_3 catalyst shows higher CO selectivity and lower CO_2 selectivity between 300 and 600 °C, compared with the standard-treated catalyst. The enhancement is attributed to the formation of well-dispersed smaller Rh nanoparticles.
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Water-treated Rh/γ-Al2O3 catalyst for Methane Partial Oxidation
Applied Petrochemical Research, 2016Co-Authors: Alan M. LaneAbstract:A water treatment technique, using H2 as a reducing agent in a wet environment, was applied to a conventional Rh/γ-Al2O3 catalyst. Both standard- and water-treated Rh/γ-Al2O3 catalysts were prepared and their catalytic performances were tested in Methane Partial Oxidation reaction. The water-treated Rh/γ-Al2O3 catalyst shows higher CO selectivity and lower CO2 selectivity between 300 and 600 °C, compared with the standard-treated catalyst. The enhancement is attributed to the formation of well-dispersed smaller Rh nanoparticles.
Thirasak Rirksomboon - One of the best experts on this subject based on the ideXlab platform.
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The Effect of Nb Loading on Catalytic Properties of Ni/Ce0.75Zr0.25O2 Catalyst for Methane Partial Oxidation
Journal of Natural Gas Chemistry, 2007Co-Authors: Sitthiphong Pengpanich, Vissanu Meeyoo, Thirasak Rirksomboon, Johannes W. SchwankAbstract:Abstract In this study, the effect of Nb loading on the catalytic activity of Ce 0.75 Zr 0.25 O 2 -supported Ni catalysts was studied for Methane Partial Oxidation. The catalysts were characterized by BET, H 2 chemisorption, XRD, TPR, TEM and tested for Methane Partial Oxidation to syngas in the temperature range of 400–800 °C at atmospheric pressure. The results showed that the activity of Methane Partial Oxidation on the catalysts was apparently dependent on Nb loading. It seemed that the addition of Nb lowered the catalytic activity for Methane Partial Oxidation and increased the extent of carbon deposition. This might be due to the strong interaction between NiO and Nb-modified support and reduction of surface oxygen reducibility.
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Methane Partial Oxidation over ni ceo2 zro2 mixed oxide solid solution catalysts
Catalysis Today, 2004Co-Authors: Sitthiphong Pengpanich, Vissanu Meeyoo, Thirasak RirksomboonAbstract:Abstract In this study, Methane Partial Oxidation (MPO) to synthesis gas over Ni/Ce 1− x Zr x O 2 ( x =0, 0.25, and 1.0 with varying Ni loading of 5, 10 and 15 wt.%) was investigated over the temperature range of 400–800 °C. The experimental results showed that the catalysts prepared by impregnation method are more active than those prepared by gel impregnation method because of their higher degrees of metal dispersion and reducibility. Under the reaction conditions, MPO over Ni/CeO 2 and Ni/Ce 0.75 Zr 0.25 O 2 mixed oxide catalysts were active at temperatures above 550 °C whereas that of Ni/ZrO 2 took place at temperatures above 650 °C. The H 2 /CO molar ratio of 2.0±0.05 was obtained. Generally, the CH 4 conversion slightly increased while the CO and H 2 selectivities remained unchanged with increasing Ni loading. The Ni/Ce 0.75 Zr 0.25 O 2 mixed oxide catalysts were found to resist to coke formation more than the other catalysts due to their high degrees of metal dispersion and surface oxygen mobility. The TPO results indicated that a major source of carbon deposition on these catalysts is due to the Methane decomposition. Results also showed that the activity and selectivity of the catalysts can be regained after the regeneration under oxidizing atmosphere.
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Methane Partial Oxidation over Ni/CeO2–ZrO2 mixed oxide solid solution catalysts
Catalysis Today, 2004Co-Authors: Sitthiphong Pengpanich, Vissanu Meeyoo, Thirasak RirksomboonAbstract:Abstract In this study, Methane Partial Oxidation (MPO) to synthesis gas over Ni/Ce 1− x Zr x O 2 ( x =0, 0.25, and 1.0 with varying Ni loading of 5, 10 and 15 wt.%) was investigated over the temperature range of 400–800 °C. The experimental results showed that the catalysts prepared by impregnation method are more active than those prepared by gel impregnation method because of their higher degrees of metal dispersion and reducibility. Under the reaction conditions, MPO over Ni/CeO 2 and Ni/Ce 0.75 Zr 0.25 O 2 mixed oxide catalysts were active at temperatures above 550 °C whereas that of Ni/ZrO 2 took place at temperatures above 650 °C. The H 2 /CO molar ratio of 2.0±0.05 was obtained. Generally, the CH 4 conversion slightly increased while the CO and H 2 selectivities remained unchanged with increasing Ni loading. The Ni/Ce 0.75 Zr 0.25 O 2 mixed oxide catalysts were found to resist to coke formation more than the other catalysts due to their high degrees of metal dispersion and surface oxygen mobility. The TPO results indicated that a major source of carbon deposition on these catalysts is due to the Methane decomposition. Results also showed that the activity and selectivity of the catalysts can be regained after the regeneration under oxidizing atmosphere.
Sitthiphong Pengpanich - One of the best experts on this subject based on the ideXlab platform.
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The Effect of Nb Loading on Catalytic Properties of Ni/Ce0.75Zr0.25O2 Catalyst for Methane Partial Oxidation
Journal of Natural Gas Chemistry, 2007Co-Authors: Sitthiphong Pengpanich, Vissanu Meeyoo, Thirasak Rirksomboon, Johannes W. SchwankAbstract:Abstract In this study, the effect of Nb loading on the catalytic activity of Ce 0.75 Zr 0.25 O 2 -supported Ni catalysts was studied for Methane Partial Oxidation. The catalysts were characterized by BET, H 2 chemisorption, XRD, TPR, TEM and tested for Methane Partial Oxidation to syngas in the temperature range of 400–800 °C at atmospheric pressure. The results showed that the activity of Methane Partial Oxidation on the catalysts was apparently dependent on Nb loading. It seemed that the addition of Nb lowered the catalytic activity for Methane Partial Oxidation and increased the extent of carbon deposition. This might be due to the strong interaction between NiO and Nb-modified support and reduction of surface oxygen reducibility.
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Methane Partial Oxidation over ni ceo2 zro2 mixed oxide solid solution catalysts
Catalysis Today, 2004Co-Authors: Sitthiphong Pengpanich, Vissanu Meeyoo, Thirasak RirksomboonAbstract:Abstract In this study, Methane Partial Oxidation (MPO) to synthesis gas over Ni/Ce 1− x Zr x O 2 ( x =0, 0.25, and 1.0 with varying Ni loading of 5, 10 and 15 wt.%) was investigated over the temperature range of 400–800 °C. The experimental results showed that the catalysts prepared by impregnation method are more active than those prepared by gel impregnation method because of their higher degrees of metal dispersion and reducibility. Under the reaction conditions, MPO over Ni/CeO 2 and Ni/Ce 0.75 Zr 0.25 O 2 mixed oxide catalysts were active at temperatures above 550 °C whereas that of Ni/ZrO 2 took place at temperatures above 650 °C. The H 2 /CO molar ratio of 2.0±0.05 was obtained. Generally, the CH 4 conversion slightly increased while the CO and H 2 selectivities remained unchanged with increasing Ni loading. The Ni/Ce 0.75 Zr 0.25 O 2 mixed oxide catalysts were found to resist to coke formation more than the other catalysts due to their high degrees of metal dispersion and surface oxygen mobility. The TPO results indicated that a major source of carbon deposition on these catalysts is due to the Methane decomposition. Results also showed that the activity and selectivity of the catalysts can be regained after the regeneration under oxidizing atmosphere.
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Methane Partial Oxidation over Ni/CeO2–ZrO2 mixed oxide solid solution catalysts
Catalysis Today, 2004Co-Authors: Sitthiphong Pengpanich, Vissanu Meeyoo, Thirasak RirksomboonAbstract:Abstract In this study, Methane Partial Oxidation (MPO) to synthesis gas over Ni/Ce 1− x Zr x O 2 ( x =0, 0.25, and 1.0 with varying Ni loading of 5, 10 and 15 wt.%) was investigated over the temperature range of 400–800 °C. The experimental results showed that the catalysts prepared by impregnation method are more active than those prepared by gel impregnation method because of their higher degrees of metal dispersion and reducibility. Under the reaction conditions, MPO over Ni/CeO 2 and Ni/Ce 0.75 Zr 0.25 O 2 mixed oxide catalysts were active at temperatures above 550 °C whereas that of Ni/ZrO 2 took place at temperatures above 650 °C. The H 2 /CO molar ratio of 2.0±0.05 was obtained. Generally, the CH 4 conversion slightly increased while the CO and H 2 selectivities remained unchanged with increasing Ni loading. The Ni/Ce 0.75 Zr 0.25 O 2 mixed oxide catalysts were found to resist to coke formation more than the other catalysts due to their high degrees of metal dispersion and surface oxygen mobility. The TPO results indicated that a major source of carbon deposition on these catalysts is due to the Methane decomposition. Results also showed that the activity and selectivity of the catalysts can be regained after the regeneration under oxidizing atmosphere.
M. Graziani - One of the best experts on this subject based on the ideXlab platform.
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Embedded Rh(1wt.%)@Al2O3: Effects of high temperature and prolonged aging under Methane Partial Oxidation conditions
Applied Catalysis B: Environmental, 2007Co-Authors: T. Montini, A.m. Condò, N. Hickey, F.c. Lovey, L. De Rogatis, P. Fornasiero, M. GrazianiAbstract:A simple synthetic procedure for the production of catalysts stable at high temperature was investigated. Methane Partial Oxidation was studied over a Rh(1%)@Al2O3 catalyst, composed of Rh nanoparticles embedded in an Al2O3 matrix, in comparison to a reference Rh(1%)/Al2O3, obtained by standard wet impregnation procedure. Both Rh catalysts are active for MPO, reaching total CH4 conversion above 1023 K. The embedded catalyst is more resistant to deactivation. The protection offered by the surrounding layer of porous oxide prevents extensive sintering of the active metal phase, even after high temperature aging. Moreover, the embedded Rh(1%)@Al2O3 is more resistant towards the undesirable incorporation of Rh into the alumina under oxidising conditions. At 1023 K, stable MPO activity is observed for at least 60 hours, after which slow deactivation starts, essentially by coking. Treatment with O2 restores the catalytic activity, while switches to O2 during reaction prevent deactivation
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Embedded Rh(1wt %)@Al2O3: Effects of high temperature and prolonged aging under Methane Partial Oxidation conditions
Applied Catalysis B-environmental, 2006Co-Authors: T. Montini, A.m. Condò, N. Hickey, F.c. Lovey, L. De Rogatis, P. Fornasiero, M. GrazianiAbstract:Abstract A simple and efficient synthetic procedure for the production of catalysts stable at high temperature was investigated. Methane Partial Oxidation was studied over a Rh(1 wt.%)@Al 2 O 3 catalyst, composed of Rh nanoparticles embedded in an Al 2 O 3 matrix, and the results were compared with those of a reference Rh(1 wt.%)/Al 2 O 3 , obtained by incipient wetness impregnation procedure. The embedded catalyst was prepared by precipitation of Al(OH) 3 in the presence of stabilised Rh nanoparticles, followed by calcination. H 2 chemisorption data confirm the accessibility of most of the protected Rh nanoparticles. Both Rh catalysts are active for MPO, reaching complete CH 4 conversion above 1023 K. Notably, the embedded catalyst is more resistant to deactivation during consecutive run-up and steady state catalytic experiments. The protection offered by the surrounding layer of porous oxide prevents extensive sintering of the active metal phase, even after high temperature aging, as observed by high resolution TEM. Moreover, with respect to the standard impregnated sample, the embedded Rh(1 wt.%)@Al 2 O 3 is more resistant towards the undesirable incorporation of Rh into the alumina under oxidising conditions. At 1023 K, stable MPO activity is observed for at least 60 h, after which slow deactivation starts, essentially by coke deposition. Treatment with O 2 restores the catalytic activity, while brief switches to O 2 during reaction prevent deactivation. Increasing the working temperature or the reactant concentration significantly reduces the effects of coke deactivation.
Huilin Wan - One of the best experts on this subject based on the ideXlab platform.
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In situ Raman Characterization on the Rh/Al2O3 Calcined at Different Temperature for Methane Partial Oxidation to Synthesis Gas
Science and Technology in Catalysis 2006, 2007Co-Authors: Weizheng Weng, Xiao Qing Pei, Fei Yang Huang, Chiian Jing Huang, Huilin WanAbstract:A comparative study using in situ Raman and TPSR techniques were performed over the Rh/Al 2 O 3 calcined at 500 to 900 °C to elucidate the effect of calcinations temperatures on the chemical state of the Rh species and its relationship with the performance of the catalysts for Methane Partial Oxidation to synthesis gas. The results indicated that the significant difference in the catalytic behavior of the Rh/Al 2 O 3 calcined in the low (500∼600 °C) and high (800∼900 °C) temperature regions can be related to the difference in the reducibility and oxygen affinity of the Rh species in the catalysts, which will consequently affect the concentration of oxygen species on the catalysts under the reaction condition.
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Influence of calcination temperature on the primary products of Methane Partial Oxidation to synthesis gas over Rh/Al2O3 catalyst
Studies in Surface Science and Catalysis, 2004Co-Authors: Weizheng Weng, Chun-rong Luo, Haiqiang Lin, Huilin WanAbstract:The reaction pathway of Methane Partial Oxidation to synthesis gas over Rh/Al2O3 calcined at 600 and 900 °C was studied by using the in situ time-resolved FTIR spectroscopy to follow the primary reaction products over the catalysts. The results of TPR and XPS characterizations suggest that the difference in the reaction mechanism of Methane Partial Oxidation to synthesis gas over the two catalysts can be related to the difference in the reducibility of the supported Rh species, which may affect the concentration of O2− species on the surface of the catalysts under the reaction conditions.