负载型钒基催化剂上丙烷的临氧活化转化

Propane Activation and Conversion over Supported Vanadia Base Catalysts in the Presence of Oxygen

用 TPSR(程序升温表面反应 ) - TR(FT) IR技术 ,研究临氧条件下丙烷在负载型钒基催化剂上的活化和转化 ,并与催化剂的可还原性和表面酸性相关联 .丙烷氧化脱氢生成丙烯与深度氧化生成 COx的起始反应温度相同 ;而裂解产物 C2 H4和 CH4的生成温度比丙烷氧化脱氢生成丙烯的高得多 ,可能主要源于丙烷的高温气相裂解 .催化剂的表面酸性位和强的可还原性 ,有利于丙烷中 C- H键的活化和临氧转化 ,降低起始反应温度和提高丙烷转化率 .但强的可还原性也易导致氧化脱氢产物丙烯的进一步氧化 。

Propane activation and conversion over supported vanadia base catalysts in the presence of oxygen were studied by Temperature Programmed Surface Reaction Time resolved Infrared Spectroscopy (TPSR TRIR). Oxidative dehydrogenation of propane to propene and deep oxidation of propane to CO x appeared to take place at the same temperature, while products C 2H 4 and CH 4 may be produced mainly from gas phase cracking of propane at high temperature. Strong reducibility and surface acidity are favorable to activate the second C-H bond in propane molecule, and result in the lowering of ignition temperature of propane oxidative dehydrogenation and increasing of the propane conversion. The adsorption of propene on acid sites leads to its total oxidation.