By taking advantage of silylanization, Al2O3 support was modified by organosilane and supported Pd-Cu-Clx/Al2O3 catalysts were prepared. The effects of hydrophobicity on catalyst stability during CO oxidation were inv...By taking advantage of silylanization, Al2O3 support was modified by organosilane and supported Pd-Cu-Clx/Al2O3 catalysts were prepared. The effects of hydrophobicity on catalyst stability during CO oxidation were investigated. The physicochemical properties and redox potential of the catalyst were characterized by N2 adsorption-desorption, XRD, H2-TPR, and XPS. In order to understand the relationship between the oxidation stability of CO and the presence of water, the CO oxidation mechanism was studied by in situ DRIFT. Support pretreatment markedly promoted catalyst stability during CO oxidation; CO conversion was 78% after 150 h at saturated humidity and freezing point. Modification led to an obvious decrease in chloride ion concentration and enhancement in hydrophobicity. The role of water in CO oxidation was complicated. The presence of water favored CO oxidation over active Pd~＋ species and Pd0 reoxidation by Cu^（2＋） species. Meanwhile, water also inhibited the formation of the active Pd~＋ species and helped to produce carbonate species. Compared with the form of the carbonate species, the inhibition of water to produce active Pd~＋ species played the main detrimental role in catalyst stability.展开更多
基金supported by the National Key Research and Development Program of China(2016YFC0204300)National Natural Science Foundation of China(21207037,21333003,21571061)+1 种基金the "Shu Guang" Project of the Shanghai Municipal Education Commission(12SG29)the Commission of Science and Technology of Shanghai Municipality(15DZ1205305)~~
文摘By taking advantage of silylanization, Al2O3 support was modified by organosilane and supported Pd-Cu-Clx/Al2O3 catalysts were prepared. The effects of hydrophobicity on catalyst stability during CO oxidation were investigated. The physicochemical properties and redox potential of the catalyst were characterized by N2 adsorption-desorption, XRD, H2-TPR, and XPS. In order to understand the relationship between the oxidation stability of CO and the presence of water, the CO oxidation mechanism was studied by in situ DRIFT. Support pretreatment markedly promoted catalyst stability during CO oxidation; CO conversion was 78% after 150 h at saturated humidity and freezing point. Modification led to an obvious decrease in chloride ion concentration and enhancement in hydrophobicity. The role of water in CO oxidation was complicated. The presence of water favored CO oxidation over active Pd~＋ species and Pd0 reoxidation by Cu^（2＋） species. Meanwhile, water also inhibited the formation of the active Pd~＋ species and helped to produce carbonate species. Compared with the form of the carbonate species, the inhibition of water to produce active Pd~＋ species played the main detrimental role in catalyst stability.
