Progress in hydrogen production over transition metal carbide catalysts: challenges and opportunities

Incorporation of carbon into metal lattices yields transition metal carbides (TMCs) with properties quite different from their parent metals and corresponding metal oxides. In this short review, we summarize the recent progress on employing TMCs as active catalysts for hydrogen (H₂) production, namely by the water-gas-shift reaction, methanol reforming, and the hydrogen evolution reaction in water electrolysis. Special interest is put on comparing the catalytic properties of TMCs with traditional metal oxide catalysts to understand the superior activities of TMCs in H₂-production reactions.