Preparation and modification of PdAg membranes by electroless and electroplating process for hydrogen separation

In this study, the PdAg membranes are prepared and applied for H₂ separation and the effect of H₂O_(g) on their permeation properties have been studied. Two kinds of surface modifications, manual or suction-assisted methods are used to reduce the pore size of the Ag substrate and the PdAg membranes are then deposited on the modified substrates by different cycles of electroless plating (ELP) and electroplating (EP) processes. The samples prepared by ELP and EP processes on manual or suction-assisted methods can reach the gas tight level with the hydrogen flux of about 0.5 or 1.1 (mol-m^− 2-s^− 1) under pressure difference of 400 kPa. In terms of the H₂O_(g) effect on the H₂ permeation, the hydrogen flux with H₂O_(g) are 0.3 and 1.0 (mol-m^− 2-s^− 1) for manual and suction modified samples, when applied pressure difference of 400 kPa and the depletion ratio is 40 and 9%, respectively, much smaller than those reported in the literature. The controlling process is mass transfer for both two samples, resulting from the competition effect of H₂ and H₂O_(g).