A composite gas separation module includes a porous metal substrate; an intermediate layer that includes a powder having a Tamman temperature higher than the Tamman temperature of the porous metal substrate and wherein the intermediate layer overlies the porous metal substrate; and a dense hydrogen-selective membrane, wherein the dense hydrogen-selective membrane overlies the intermediate layer. In another embodiment, a composite gas separation module includes a porous metal substrate; an intermediate powder layer; and a dense gas-selective membrane, wherein the dense gas-selective membrane overlies the intermediate powder layer.