Iridium Cluster Anchored onto Cubic Molybdenum Carbide with Strong Electronic Interactions for Robust Hydrogen Oxidation Reaction in Alkaline Medium

Abstract Constructing atomic‐scale dispersed noble metal electrocatalysts holds enormous potential toward alkaline hydrogen oxidation reactions (HOR) owing to the high intrinsic activity and atom utilization. Here, this work shows that Ir clusters anchored on different types of molybdenum carbides (Ir/α‐MoC_1‐x, Ir/β‐Mo₂C) with tunable electronic interactions display distinct performance in alkaline HOR. Notably, the mass activity of Ir/α‐MoC_1‐x with stronger electronic interaction is roughly twice that of Ir/β‐Mo₂C. Moreover, the Ir/α‐MoC_1‐x has reached an impressive mass‐normalized exchange current density (j_{0, mass}) of 320 mA mg⁻¹_metal, making the HOR properties are comparable to those recently reported excellent alkaline HOR Ir‐based electrocatalysts. Both experimental and theoretical calculations have confirmed that the strong metal‐substrate interaction of Ir/α‐MoC_1‐x via interfacial Ir‐Mo bonding, leading to a significantly modulated electronic structure and optimized binding energy of H* and OH*, thereby promoting the reaction kinetics of alkaline HOR. This work highlights strong metal‐support interactions can be an effective scheme for regulating the local electronic configuration and adsorption behavior of the catalyst along with an improved intrinsic catalytic activity.