Subnanometer Bimetallic Platinum–Zinc Clusters in Zeolites for Propane Dehydrogenation
Qiming Sun, Ning Wang, Qiyuan Fan, Lei Zeng, Álvaro Mayoral, Shu Miao, Ruoou Yang, Zheng Jiang, Wei Zhou, Jichao Zhang, Tianjun Zhang, Jun Xu, Peng Zhang, Jun Cheng, Dongchun Yang, Ran Jia, Lin Li, Qinghong Zhang, Ye Wang, Osamu Terasaki, Jihong Yu
Abstract
Abstract Propane dehydrogenation (PDH) has great potential to meet the increasing global demand for propylene, but the widely used Pt‐based catalysts usually suffer from short‐term stability and unsatisfactory propylene selectivity. Herein, we develop a ligand‐protected direct hydrogen reduction method for encapsulating subnanometer bimetallic Pt–Zn clusters inside silicalite‐1 (S‐1) zeolite. The introduction of Zn species significantly improved the stability of the Pt clusters and gave a superhigh propylene selectivity of 99.3 % with a weight hourly space velocity (WHSV) of 3.6–54 h −1 and specific activity of propylene formation of 65.5 mol g Pt −1 h −1 (WHSV=108 h −1 ) at 550 °C. Moreover, no obvious deactivation was observed over PtZn4@S‐1‐H catalyst even after 13000 min on stream (WHSV=3.6 h −1 ), affording an extremely low deactivation constant of 0.001 h −1 , which is 200 times lower than that of the PtZn4/Al 2 O 3 counterpart under the same conditions. We also show that the introduction of Cs + ions into the zeolite can improve the regeneration stability of catalysts, and the catalytic activity kept unchanged after four continuous cycles.