just one gas permeation of the 1-?m-thick g-C3N4 membrane at space temperature and one??bar. The inset displays the gas selectivity for H2 above other gases. b Permeance and separation components with the one-?m-thick g-C3N4 membranes in the equimolar combined-gas permeation at space temperature and 1??bar. Inset reveals the kinetic diameters of va