Bimetallic CoCu-modified Pt species in S-1 zeolite with enhanced stability for propane dehydrogenation

Abstract

Propane dehydrogenation (PDH) has been an outstanding technique with a bright prospect, which can meet the growing global demand for propylene. However, undesired side reactions result in the deactivation of the Pt-based catalysts, which contribute to the insufficient lifetime of the catalysts. Herein, we describe a novel catalyst by encapsulating bimetallic CoCu-modified Pt species in S-1 zeolite for efficient dehydrogenation of propane, which synergizes the confinement of zeolites and the geometric and electronic effects on Pt species for enhancing the catalyst stability. The introduction of bimetallic additives efficiently promotes the dispersion of platinum and the electron transfer between Pt species and the additives, which greatly prolongs the lifetime of the catalysts. Particularly, no obvious deactivation is observed on 0.2Pt0.3Co0.5CuK@S-1 after 93 h on stream with a weight hourly space velocity (WHSV) of 5.4 h−1, revealing an ultralow deactivation constant of 0.0011 h−1 (t = 909 h). The formation rate of propylene still maintains at a high value of 407 mol gPt-1 h−1 (WHSV = 21.6 h−1) at 580 ℃ even after on pure propane stream for 42 h. The catalyst with the bimetallic CoCu-modified Pt species in S-1 zeolite reveals ultra-high activity and stability for PDH, which is ascribed to the highly dispersed Pt species and the stabilization effect of bimetallic additives on Pt species.