Silver(I) N–heterocyclic carbene complex encapsulated in cellulose acetate membranes for hydrogen gas purification

Abstract

Coinage metal complexes bearing N–heterocyclic carbene (NHC) ligands are important in discovery of new metal-based drugs, however, their usage in homogenous and heterogeneous catalysis, photocatalysis, gas purification, etc., are scarce. In this report, the performance of a silver(I)–NHC encapsulated membrane for hydrogen gas purification is reported. Gas purification materials or membranes play a crucial role in the manufacture of pure hydrogen gas, a green fuel, at industrial levels. The purification of hydrogen gas has been carried out conventionally following solid-state diffusion method using silver-palladium metal alloy-based membranes. Though the efficiency of these membranes is acceptable, their cost of preparation is economically nonviable, and hence a new method has been developed to purify hydrogen gas using silver(I)-NHC complex encapsulated cellulose acetate membranes. The complex encapsulated membranes possess promising elongation strength and tensile modulus. The optimum composite membrane showed good separation efficiency with ideal selectivity of 2.0, 65 and 32 for H2/CO2, H2/CH4 and CO2/CH4, respectively.