Pd/HAp/Hastelloy Composite Membrane with Enhanced Hydrogen Permeability and Stability for Industrial Applications

Abstract A major challenge in the current energy transition toward environmentally benign energy carriers such as hydrogen is the complexity and low productivity of existing production routes. The development of high-performance membrane reactors and H2-selective membranes for such systems is one of the most promising ways to address this problem. This work considers the scalingup of composite Pd membranes for application in industrial hydrogen separation and production processes. This paper examines the potential for scaling up composite Pd membranes for use in industrial hydrogen separation and production processes. A new approach to producing composite membranes has been developed, involving the formation of a selective Pd layer by chemical deposition, which is more technologically advanced, simpler, and suitable for scaling up and industrial production. A two-step hydroxyapatite deposition method, involving filling the large pores of the substrate and forming a smooth ceramic surface with minimal porosity, yielded a thin, uniform, defect-free selective Pd layer with high adhesion and effectively resolved the interdiffusion issue, ensuring membrane structural stability. By reducing the thickness of the selective layer and, consequently, shortening the diffusion path of atomic hydrogen, the developed Pd/HAp/Hastelloy X composite membrane is capable of increasing hydrogen flux by more than 20 times compared to a bulk Pd membrane. Stability over 100 h of testing at temperatures of 200–400°C and high hydrogen flow values comparable to analogues and even exceeding them were also demonstrated. The selectivity of the composite membrane (>1500) points to a dense selective layer with no detectable defects. The obtained results confirm the potential of the developed method for producing composite Pd membranes and the possibility of their use in steam reforming reactors in the processes of hydrogen production and purification.