Palladium membranes applications in reaction systems for hydrogen separation and purification: A review

Abstract Application of palladium-based membrane technology in chemical reactions is currently focused on producing ultrapure hydrogen. Due to the environmental concerns and undesirable side effects of greenhouse gases, hydrogen has great potential as an alternative future fuel. Pd-alloy membranes have demonstrated tremendous potential for the hydrogen extraction in hydrogen-dependent reactions. Numerous studies have been done investigating the diffusion of hydrogen through palladium membranes. In this review, the ability of Pd-alloy membrane reactors in the removal of hydrogen from water gas shift, steam reforming, and dehydrogenation reactions is evaluated. This review is divided into several sections including palladium membranes, Pd-alloy membranes, composite Pd-based membranes, and their preparation methods Moreover, the hydrogen permeation rate, Sieverts’ law, Damkohler-Peclet product design parameter, and various membrane reactors will be discussed in detail. There is also an overview of the last-decade researches on Pd-based membrane reactors. Finally, some essential ideas for the improvement of future membrane technology are proposed.