The nature of active sites in Pt–ReO_X/TiO_2 catalysts for selective hydrogenation of carboxylic acids to alcohols  

作　　者：Alexey Suknev Vladimir Zaikovskii Vasily Kaichev Eugenii Paukshtis Ekaterina Sadovskaya Bair Bal'zhinimaev 

机构地区：[1]Boreskov Institute of Catalysis SB RAS [2]Novosibirsk State University

出　　处：《Journal of Energy Chemistry》2015年第5期646-654,共9页能源化学（英文版）

摘　　要：The highly dispersed Pt-ReOx （x _〈 1 ） sites ca. 0.5 nm in size were formed via a successive and strong inter- action of the Re precursor with titania and then of the Pt complex with deposited low-valent rhenium oxide clusters. The size, charge and chemical composition were characterized by means of HRTEM/STEM with EDX mapping, XPS, and FTIRS. These sites with Re/Pt = 2 were shown to be highly active and selective in the hydrogenation of carboxylic acid to alcohol under very mild conditions （T = 130 ℃, P = 50 bar）. The reaction rate constant for the hydrogenation of hexanoic acid increased linearly with the Pt content. As for the homogeneous pincer-type Ru-organic complexes, the active Pt-ReOx sites can dissociate heterolytically the molecular hydrogen with the formation of hydroxyl groups and Pt hydride for hydrogenation of the carboxylic group. Indeed, TOF of 20 h 1 and selectivity of 98%-99% are approaching the values typical of homogeneous catalysts. The first order kinetics described well the experimental data obtained in a wide range of reaction conditions.The highly dispersed Pt-ReOx （x _〈 1 ） sites ca. 0.5 nm in size were formed via a successive and strong inter- action of the Re precursor with titania and then of the Pt complex with deposited low-valent rhenium oxide clusters. The size, charge and chemical composition were characterized by means of HRTEM/STEM with EDX mapping, XPS, and FTIRS. These sites with Re/Pt = 2 were shown to be highly active and selective in the hydrogenation of carboxylic acid to alcohol under very mild conditions （T = 130 ℃, P = 50 bar）. The reaction rate constant for the hydrogenation of hexanoic acid increased linearly with the Pt content. As for the homogeneous pincer-type Ru-organic complexes, the active Pt-ReOx sites can dissociate heterolytically the molecular hydrogen with the formation of hydroxyl groups and Pt hydride for hydrogenation of the carboxylic group. Indeed, TOF of 20 h 1 and selectivity of 98%-99% are approaching the values typical of homogeneous catalysts. The first order kinetics described well the experimental data obtained in a wide range of reaction conditions.

关 键 词：Selective hydrogenation Hexanoic acid Hexanol PlatinumRhenium Nanoparticles 

分 类 号：O643.36[理学—物理化学]