A hybrid processing method for high performance hydrogen-selective silica membranes

Development of high performance hydrogen-selective inorganic membrane has become an important requisite for the production of hydrogen, an energy carrier that could cater the ongoing energy revolution. This paper describes a novel, hybrid method to process high performance hydrogen perm-selective membranes by the rapid CVD modification of a sol–gel silica layer. The initial N2 permeance values through a membrane were brought down by four orders of magnitude to 2.74 × 10−10 mol m−2 s−1 Pa−1 within 5 min of CVD, while maintaining the H2 permeance values as high as 6.43 × 10−7 mol m−2 s−1 Pa−1 (H2/N2 = 2300). It is likely that the reduction in the CVD zone thickness achieved by the presence of pre-existing sol–gel silica layer is the reason for the rapid modification of the pore structure to high performance membranes.