Effect of preparation method on active sites variation for catalytic oxidation of toluene over Pt/MCM-48.

Toluene oxidation behavior has been investigated on a series of catalysts with Pt supported on MCM-48 that has a large specific surface area & easy-transported three-dimensional channels prepared by four different methods. It was found that various introduction ways of Pt have a great influence on both Pt content and state, resulting in a difference in catalytic oxidation performance. Pt/M48-PG prepared via the post-grafting method possesses both the highest Pt content (0.83 wt%) and active species of Pt0 & surface labile oxygen (accounting for 46% and 55%, respectively), resulting in the lowest T 90 (155 °C) and the highest TOF (7.92 ×10−3·s−1). Characterization results showed that the amine functional groups could be successfully grafted onto the support's surface, which is beneficial for the binding of platinum precursor with support, leading to the high actual loading efficiency and dispersion of Pt, both of which contribute to retaining more Pt0 and surface labile oxygen active species. [Display omitted] • Evolution on Pt/MCM-48′s property by different preparation methods is discussed. • The usage efficiency of Pt was significantly increased by post-grafting method. • The post-grafting method enhanced the catalyst's capacity for Pt0 retention. • Discussion over the connection among Pt0, reactive oxygen and catalytic performance. [ABSTRACT FROM AUTHOR]