Interface-Engineering Strategy for Boosting Low-Ir Catalytic Water Oxidation Using a Conductive Ti4O7 Support

The need to use expensive and scarce Ir-based catalysts in the oxygen evolution reaction (OER) hinders the large-scale application of proton exchange membrane water electrolysis (PEMWE). Herein, we present an effective interface-engineering strategy to boost the efficacy of low-Ir catalysis of OER by means of electron transfer and lattice oxygen stabilization at the catalyst–support interface by utilizing a highly conductive (∼960 S cm–1) Ti4O7 support to strongly anchor IrO2 nanoparticles. Experimental and theoretical calculations suggest that Ti4O7 tailors the Ir electronic structure that results from the formation of Ir–O–Ti bonds at the IrO2–Ti4O7 interface, resulting in a lowered d-band center that weakens the adsorption of oxygen intermediates on Ir sites and thus boosts OER catalysis. The Ir–O–Ti bonds formed at the interface stabilize lattice oxygen in IrO2, facilitating a stable lattice oxygen mechanism path for OER catalysis. The interface effect results in superior OER activity with an overpotential of 244 mV at 10 mA cm–2 and a high mass activity of 1342.9 A gIr–1 (93.25× that of commercial IrO2), and the material also shows better durability than commercial IrO2. This interface-engineering strategy affords a strong catalyst–support interaction and should facilitate the design of high-performance catalysts for PEMWE applications.