Effect of Nb content on hydrothermal stability of a novel ethylene-bridged silsesquioxane molecular sieving membrane for H2/CO2 separation

► Hybrid silica membranes with various Nb content were fabricated via sol-gel route. ► Nb-hybrid silica membranes showed sufficient high H2/CO2 permselectivities. ► Those membranes exhibited excellent stability in the presence of 150 kPa steam.