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Influence of preparation method on the nanocrystalline porosity of α-Al2O3 and the catalytic properties of Pd/α-Al2O3 in selective acetylene hydrogenation / Sataporn Komhom in Industrial & engineering chemistry research, Vol. 48 N° 13 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6273–6279 Titre : Influence of preparation method on the nanocrystalline porosity of α-Al2O3 and the catalytic properties of Pd/α-Al2O3 in selective acetylene hydrogenation Type de document : texte imprimé Auteurs : Sataporn Komhom, Auteur ; Okorn Mekasuwandumrong, Auteur ; Joongjai Panpranot, Auteur Année de publication : 2009 Article en page(s) : pp. 6273–6279 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nanocrystalline  α-Al2O3  powder  Crystallite  sizes Résumé : Nanocrystalline α-Al2O3 powder with average crystallite sizes of 34−68 nm have been synthesized by three different methods, namely, solvothermal, sol−gel, and precipitation. Although the smallest crystallite size of α-Al2O3 was obtained via the sol−gel synthesis, the α-Al2O3 sol−gel possessed the least amount of specific surface area and pore volume. A narrow pore size distribution with an average pore diameter of 15 nm can be obtained via solvothermal method, whereas the precipitation method yielded α-Al2O3 with larger pore size and a wider pore size distribution. When used as a support for palladium catalysts, the α-Al2O3 solvothermal provided the highest palladium dispersion and the best catalyst performance in selective hydrogenation of acetylene. The catalytic properties of Pd/α-Al2O3 solvothermal were improved, in terms of both acetylene conversion and ethylene selectivity. As shown by temperature program studies, the use of solvothermal-derived α-Al2O3 facilitated H2 reduction at low temperature and the desorption of ethylene and CO. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801784f [article] Influence of preparation method on the nanocrystalline porosity of α-Al2O3 and the catalytic properties of Pd/α-Al2O3 in selective acetylene hydrogenation [texte imprimé] / Sataporn Komhom, Auteur ; Okorn Mekasuwandumrong, Auteur ; Joongjai Panpranot, Auteur . - 2009 . - pp. 6273–6279. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6273–6279 Mots-clés : Nanocrystalline  α-Al2O3  powder  Crystallite  sizes Résumé : Nanocrystalline α-Al2O3 powder with average crystallite sizes of 34−68 nm have been synthesized by three different methods, namely, solvothermal, sol−gel, and precipitation. Although the smallest crystallite size of α-Al2O3 was obtained via the sol−gel synthesis, the α-Al2O3 sol−gel possessed the least amount of specific surface area and pore volume. A narrow pore size distribution with an average pore diameter of 15 nm can be obtained via solvothermal method, whereas the precipitation method yielded α-Al2O3 with larger pore size and a wider pore size distribution. When used as a support for palladium catalysts, the α-Al2O3 solvothermal provided the highest palladium dispersion and the best catalyst performance in selective hydrogenation of acetylene. The catalytic properties of Pd/α-Al2O3 solvothermal were improved, in terms of both acetylene conversion and ethylene selectivity. As shown by temperature program studies, the use of solvothermal-derived α-Al2O3 facilitated H2 reduction at low temperature and the desorption of ethylene and CO. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801784f

Preparation of nano-Pd/SiO2 by one-step flame spray pyrolysis and its hydrogenation activities / Okorn Mekasuwandumrong in Industrial & engineering chemistry research, Vol. 48 N° 6 (Mars 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 6 (Mars 2009) . - pp. 2819–2825 Titre : Preparation of nano-Pd/SiO2 by one-step flame spray pyrolysis and its hydrogenation activities : comparison to the conventional impregnation method Type de document : texte imprimé Auteurs : Okorn Mekasuwandumrong, Auteur ; Sirima Somboonthanakij, Auteur ; Piyasan Praserthdam, Auteur Année de publication : 2009 Article en page(s) : pp. 2819–2825 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nano-Pd/SiO2  catalysts  Flame  spray  pyrolysis  Conventional  impregnation  method Résumé : Characteristics and catalytic properties of the nano-Pd/SiO2 catalysts synthesized in one-step flame spray pyrolysis (FSP) were compared to those prepared on the flame-made SiO2 supports by conventional impregnation method. Pd0 metal particles/clusters <3 nm in size were obtained directly from a single-step flame process, whereas the conventional impregnation method resulted in PdO with larger crystallite sizes (in the range of 5−12 nm). Although there was little difference in the turnover frequency (TOF) values for 1-heptyne hydrogenation on the different Pd/SiO2 catalysts prepared by impregnation, the TOF values of the flame-made catalysts decreased from 66.2 s−1 to 4.3 s−1 as the palladium loading increased from 0.5 wt % to 10 wt %, which suggested changes in the catalytic properties when palladium nanoparticles were formed simultaneously in the support matrices by FSP method. For both preparation methods, the palladium particle sizes remained unaltered after liquid-phase hydrogenation reaction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012055 [article] Preparation of nano-Pd/SiO2 by one-step flame spray pyrolysis and its hydrogenation activities : comparison to the conventional impregnation method [texte imprimé] / Okorn Mekasuwandumrong, Auteur ; Sirima Somboonthanakij, Auteur ; Piyasan Praserthdam, Auteur . - 2009 . - pp. 2819–2825. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 6 (Mars 2009) . - pp. 2819–2825 Mots-clés : Nano-Pd/SiO2  catalysts  Flame  spray  pyrolysis  Conventional  impregnation  method Résumé : Characteristics and catalytic properties of the nano-Pd/SiO2 catalysts synthesized in one-step flame spray pyrolysis (FSP) were compared to those prepared on the flame-made SiO2 supports by conventional impregnation method. Pd0 metal particles/clusters <3 nm in size were obtained directly from a single-step flame process, whereas the conventional impregnation method resulted in PdO with larger crystallite sizes (in the range of 5−12 nm). Although there was little difference in the turnover frequency (TOF) values for 1-heptyne hydrogenation on the different Pd/SiO2 catalysts prepared by impregnation, the TOF values of the flame-made catalysts decreased from 66.2 s−1 to 4.3 s−1 as the palladium loading increased from 0.5 wt % to 10 wt %, which suggested changes in the catalytic properties when palladium nanoparticles were formed simultaneously in the support matrices by FSP method. For both preparation methods, the palladium particle sizes remained unaltered after liquid-phase hydrogenation reaction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012055