Synergistic effect of scattered rare metals on Pt/CeO2 for propane oxidative dehydrogenation with CO2

Abstract

The oxidative dehydrogenation of propane with CO₂ (CO₂-ODP) is a green industrial process for producing propene. Cerium oxide-supported platinum-based (Pt/CeO₂) catalysts exhibit remarkable reactivity toward propane and CO₂ due to the unique delicate balance of C–H and CO bond activation. However, the simultaneous activation and cleavage of C–H, C–C, and C–O bonds on Pt/CeO₂-based catalysts may substantially impede the selective activation of C–H bonds during the CO₂-ODP process. Here, we report that the scattered rare metal oxide (SRO_x, SR = Ga, In) overlayer on Pt/CeO₂ exhibits extraordinary activity and selectivity for the CO₂-ODP reaction. With the assistance of Pt, the SRO_x-Pt/CeO₂ could achieve a propane conversion of 38.13% and a CO₂ conversion of 67.72%. More importantly, the selectivity of the product propene has increased from 33.28% to 88.24%, a level that is even comparable to the outstanding performance of currently reported PtSn/CeO₂ catalysts. A mechanistic study reveals that the strong affinity of the overlayer SRO_x to the propane reduces the barrier of C–H bond activation and balances the C–H cleavage rates and the C–O bond groups, accounting for the excellent selective CO₂-ODP performance of SRO_x-Pt/CeO₂ catalysts. The SRO_x-modified Pt/CeO₂ strategy offers a novel approach to modulating CO₂-ODP, thereby facilitating the highly selective preparation of propene.