Deposition of an ultrathin palladium (Pd) coating on SAPO-34 membranes for enhanced H_2/N_2 separation

摘要

Hydrogen energy has attracted great attention due to its properties of high energy transferring efficiency and zero pollution emission. Zeolite membranes are promising candidates for H-2 separation because of their uniform, molecular-sized pores and high thermal and mechanical stabilities. However, thicker membranes or modification treatments are often necessary to eliminate the defects formed during synthesis and post calcination, leading to low gas permeance. Herein, we reported the deposition of an ultrathin palladium (Pd) coating on SAPO-34 membranes to improve H-2 separation performance. H-2/N-2 selectivity was greatly increased by deposition of an ultrathin Pd coating on SAPO-34 membranes, while maintaining similar H-2 permeance. This might be attributed to the dissociative adsorption and associative desorption of H-2 on Pd, as well as fast diffusion of H-2 through ultrathin Pd coating. We also noticed that excessive Pd deposition would lead to the formation of cracks on SAPO-34 membranes, leading to deteriorated membrane performance. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.