Bifunctional Catalysts with Separated and Tunable Sites on Zeolites for Relay Catalysis of the Oxidative Dehydrogenation of Propane Using CO2

The oxidative dehydrogenation of propane using (CO2-ODH) technology has broad application prospects in the production of propylene and the utilization of CO2, and the development of efficient CO2-ODH catalysts is of great significance. However, it remains a challenge to develop a highly efficient catalyst that can activate both C & horbar;H and C & boxH;O. Herein, a PtZn/Co@S-1 catalyst with a very low precious metal content of 0.2 wt.% is reported. Benefiting from the PtZn4 nanoclusters dispersed on the surface of Silicalite-1 zeolite and tetrahedrally coordinated Co2+ in the Silicalite-1 zeolite framework via relay catalysis, the independent dual sites structure (PtZn/Co@S-1) greatly promotes CO2-ODH reaction with a high conversion rate of both C3H8 (59.7%) and CO2(44.3%), and propylene selectivity of 94.9%, thus upsetting the equilibrium for direct dehydrogenation of propane. Experimental measurements and density functional theory calculations suggest that the PtZn4 and Co2+ interfaces are likely propane dehydrogenation and carbon dioxide hydrogenation active sites respectively.