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

Abstract

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 g_Ir^–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.