Beyond Hydrogen Storage: Metal Hydrides for Catalysis

Metal hydrides (MHs) are featured for their reversible hydrogen absorption and desorption properties, which are conventionally used as hydrogen storage materials. MHs can also be used for catalysis, particularly for chemical reactions that involve hydrogen. This Review summarizes the historical and recent progress in the catalytic application of MHs. The focus topic is how the reversible hydrogen absorption and desorption properties of MHs enable their catalytic effect in hydrogen involving chemical reactions. We start with the basic properties of MHs, and their applications in hydrogen storage and related fields. The application of MHs in four important catalytic reactions: olefin hydrogenation, reversible hydrogen storage in liquid organic hydrogen carriers, CO2 hydrogenation, and NH3 synthesis are discussed. Finally, we compare MH-based catalysts with their analogues, including hydrogen spillover, oxyhydrides, mixed-anion hydrides, and electrides in catalysis. The Review demonstrates the inherent relationship between MH catalysis and their intrinsic hydrogen absorption and desorption properties, providing insights into diverse applications of MHs beyond hydrogen storage.