Palladium-niobium bimetallic doped organosilica membranes for H2/CO2 separation

Abstract

Abstract In this work, high-performance palladium-niobium doped 1,2-bis(triethoxysilyl)ethane (Pd–Nb-BTESE) membranes were prepared for H2/CO2 separation by using the sol-gel method. Nb was first incorporated into the organosilica networks in the form of Nb–O–Si covalent bonds, while Pd nanoparticles were successfully embedded into the networks with size of 5–10 nm. Based on the synergetic effects of Pd–Nb doping, the as-prepared membranes showed more appropriate structures for H2/CO2 separation. By controlling the same doping amount of Nb and changing Pd doping contents (n (Pd): n(Si) = 0.05–0.4), we found that the Pd–Nb-BTESE membrane with higher Pd doping content showed higher H2/CO2 permselectivity and stronger H2 adsorption capacity. The H2/CO2 separation performance of all the prepared Pd–Nb-BTESE membranes surpass the upper bound 2008. The membrane with n (Pd): n (Si) of 0.4 showed a superior H2/CO2 permselectivity of 107 and a high H2 permeance of 1.12 × 10−7 mol m−2 s−1·Pa−1. Our findings provide novel insights into tailoring and functionalizing organosilica membranes through bimetallic doping for practical applications.