Interface-Engineering\nStrategy for Boosting Low-Ir\nCatalytic Water Oxidation Using a Conductive Ti<sub>4</sub>O<sub>7</sub> Support

The need to use expensive and scarce Ir-based catalysts\nin the\noxygen evolution reaction (OER) hinders the large-scale application\nof proton exchange membrane water electrolysis (PEMWE). Herein, we\npresent an effective interface-engineering strategy to boost the efficacy\nof low-Ir catalysis of OER by means of electron transfer and lattice\noxygen stabilization at the catalyst–support interface by utilizing\na highly conductive (∼960 S cm<sup>–1</sup>) Ti<sub>4</sub>O<sub>7</sub> support to strongly anchor IrO<sub>2</sub> nanoparticles.\nExperimental and theoretical calculations suggest that Ti<sub>4</sub>O<sub>7</sub> tailors the Ir electronic structure that results from\nthe formation of Ir–O–Ti bonds at the IrO<sub>2</sub>–Ti<sub>4</sub>O<sub>7</sub> interface, resulting in a lowered\nd-band center that weakens the adsorption of oxygen intermediates\non Ir sites and thus boosts OER catalysis. The Ir–O–Ti\nbonds formed at the interface stabilize lattice oxygen in IrO<sub>2</sub>, facilitating a stable lattice oxygen mechanism path for\nOER catalysis. The interface effect results in superior OER activity\nwith an overpotential of 244 mV at 10 mA cm<sup>–2</sup> and\na high mass activity of 1342.9 A g<sub>Ir</sub><sup>–1</sup> (93.25× that of commercial IrO<sub>2</sub>), and the material\nalso shows better durability than commercial IrO<sub>2</sub>. This\ninterface-engineering strategy affords a strong catalyst–support\ninteraction and should facilitate the design of high-performance catalysts\nfor PEMWE applications.