Deposition of an ultrathin palladium (Pd) coating on SAPO-34 membranes for enhanced H2/N2 separation

Abstract 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 H2 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 H2 separation performance. H2/N2 selectivity was greatly increased by deposition of an ultrathin Pd coating on SAPO-34 membranes, while maintaining similar H2 permeance. This might be attributed to the dissociative adsorption and associative desorption of H2 on Pd, as well as fast diffusion of H2 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.