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

Abstract The oxidative dehydrogenation of propane using CO₂ (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─H and C═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.