Innovative Approach to Hydrogen Purification: A Review on the Role of Metal Hydrides

Abstract

Metal hydrides, renowned for their unique hydrogen bonding capabilities, have emerged as pivotal materials in the energy sector, particularly for hydrogen storage and purification applications. Their ability to store hydrogen reversibly under moderate conditions has positioned them at the forefront in hydrogen-based energy systems. This review systematically examines metal hydride–based hydrogen purification technology, addressing a significant gap in the literature where focused reviews on this specific application remain relatively scarce. The review provides a critical analysis of diverse hydrogen production methods, including steam methane reforming, gasification and pyrolysis and their subsequent purification requirements to meet stringent ISO 14687:2019 standards. Various industrial purification techniques including cryogenic separation, pressure swing adsorption and membrane-based methods are critically evaluated. Special emphasis is placed on metal hydride systems, which demonstrate lower initial capital costs, reduced operational expenditures and operation at near-ambient conditions. By consolidating scattered research findings from experimental, computational and numerical studies spanning four decades, this review systematically organises fundamental principles, materials selection criteria, thermodynamic considerations, kinetic modelling approaches, reactor design strategies, impurity tolerance mechanisms and current research trends, thereby advancing the practical implementation of this sustainable purification technology for the emerging hydrogen economy.