Bifunctional Catalysts with Separated and Tunable Sites on Zeolites for Relay Catalysis of the Oxidative Dehydrogenation of Propane Using CO<sub>2</sub>
Wanting Li, Tianchang Wang, Xinxin Cao, Yuze Li, Gai Miao, Nannan Sun, Jiong Li, Wei Han, Wei Wei, Xinqing Chen
Abstract
Abstract The oxidative dehydrogenation of propane using CO 2 (CO 2 ‐ODH) technology has broad application prospects in the production of propylene and the utilization of CO 2 , and the development of efficient CO 2 ‐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 PtZn 4 nanoclusters dispersed on the surface of Silicalite‐1 zeolite and tetrahedrally coordinated Co 2+ in the Silicalite‐1 zeolite framework via relay catalysis, the independent dual sites structure (PtZn/Co@S‐1) greatly promotes CO 2 ‐ODH reaction with a high conversion rate of both C 3 H 8 (59.7%) and CO 2 (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 PtZn 4 and Co 2+ interfaces are likely propane dehydrogenation and carbon dioxide hydrogenation active sites respectively.