Transition metal carbides and nitrides as catalysts for thermochemical reactions

[Display omitted] •Transition metal carbides and nitrides have been used as catalysts or supports.•They show promise in HDO, HDN, HDS, CO2 reduction, alcohol reforming, and WGS reactions.•Experimental and DFT studies on model surfaces and powders provide mechanistic insights.•Challenges and opportunities for utilizing TMCs and TMNs are discussed. Transition metal carbides and nitrides (TMCs and TMNs) have attracted much attention due to their unique physical and chemical properties brought by the incorporation of interstitial carbon and nitrogen into the crystal lattice of the parent metals. Recent advances in utilizing TMCs and TMNs have revealed their intriguing catalytic properties in many industrially important reactions, including heteroatom removal, CO2 activation, alcohol reforming, and water–gas shift reactions. The promising activity, selectivity, and stability of TMCs and TMNs, either as catalysts or as supports for other metals, are often attributed to their strong interactions with the adsorbates, tunable surface properties, as well as the synergy with supported metals. This review summarizes the synthesis and characterization of TMC and TMN model surfaces and powder catalysts, and uses several case studies to demonstrate their unique catalytic properties in these important reactions. A discussion is also provided regarding the challenges and opportunities associated with the utilization of TMCs and TMNs in thermocatalysis.