Research Trends in the Catalytic Applications of Metal Hydrides

Metal hydrides are traditionally known for their hydrogen storage abilities under specific temperature and pressure conditions. However, recent studies suggest their possible applications as a catalyst and catalyst promotor. This article introduces metal hydride applications in three different areas: the hydrogenation and the dehydrogenation of Liquid organic hydrogen carriers, ammonia synthesis, CO<sub>2</sub> hydrogenation and CO<sub>2</sub> reduction. The key mechanisms explored include the direct participation of the absorbed lattice hydrogen in catalytic surface reactions, creation of new hydrogen transfer path between the hydrogen and the organic substrate, and surface decomposition of the parent hydride into highly active interfacial phases, such as Ni-LaN for ammonia, and Ni-O-La for CO<sub>2</sub> hydrogenation. Case studies involving YH<sub>3</sub> and LaNi<sub>5</sub> illustrate how these materials function not merely as static hydrogen reservoirs but as dynamic systems that serve as hydrogen donors, and structural templates for generating unique active sites. This review highlights a paradigm shift in understanding metal hydrides as multifunctional materials that bridge the gap between hydrogen storage and heterogeneous catalysis.