Coordinatively Unsaturated IrC3 Single-Atom Catalysts for Efficient Methanol Oxidation Reaction.

Methanol oxidation reaction (MOR) plays a crucial role in renewable energy conversion and storage, where the key steps involve dehydrogenation and subsequent *CO electrooxidation. However, *CO oxidation remains challenging due to its strong adsorption and insufficient *OH species at active sites, severely limiting reaction kinetics. Here, the single Ir atom catalyst with abundant coordinatively unsaturated IrC3 sites is developed to electrocatalysis MOR under elevated temperature, the IrC3 sites with stronger CH3OH adsorption and weaker *CO adsorption, which break the scaling relationship between methanol and *CO adsorption energy. Moreover, the IrC3 could accelerate the electrochemical water dissociation with assistance of protophilic IrC4 to form adsorbed *OH. The balanced adsorption energy and the appearance of ample *OH would efficiently decrease the reaction energy barriers, and further accelerate the methanol dehydrogenation and *CO oxidation. By assemble the high temperature polymer electrolyte membrane electrolyzer (HT-PEME) with IrC3 sites at 180°C, it shows an excellent MOR efficiency with onset potential about 0.05 V and H2 generation rate with 8694 molH2 molIr -1 h-1 at cathode, which is much higher than that of Ir-C SACs parent catalyst and Pt/C catalysts. This finding provides an avenue to conquer the formidably sluggish kinetics of MOR for hydrogen utilization.