Well-alloyed Pt–Sb/Si-Beta from surface organometallic chemistry for propane dehydrogenation

Abstract

A surface organometallic chemistry strategy was applied for the synthesis of a highly dispersed bimetallic Pt–Sb/Si-Beta catalyst for propane dehydrogenation. A heterobimetallic complex PtCl₂(SbPh₃)₂ with a unique Pt–Sb bond was synthesized and then grafted onto the Si-Beta zeolite, which leads to the formation of the surface complex Pt(SbPh₃)₂/Si-Beta. Pt–Sb/Si-Beta was obtained via the controllable hydrogenation of Pt(SbPh₃)₂/Si-Beta. The Pt–Sb bond in the surface complex facilitates the formation of Pt–Sb bimetallic clusters, and the chemical interaction between the Pt(SbPh₃)₂ fragment and Si-Beta support effectively prevents the agglomeration of metal clusters, thereby promoting the generation of well-dispersed Pt–Sb clusters at the surface of Si-Beta. The improved activity in Pt–Sb/Si-Beta is attributed to the formation of ultra-small Pt–Sb clusters, and the enhanced selectivity is owing to the segregation of Pt with Sb in Pt–Sb clusters.