Regulating Strain\nand Electronic Structure of Indium\nTin Oxide Supported IrO<sub><i>x</i></sub> Electrocatalysts\nfor Highly Efficient Oxygen Evolution Reaction in Acid

The development of proton exchange membrane water electrolysis\nis a promising technology for hydrogen production, which has always\nbeen restricted by the slow kinetics of the oxygen evolution reaction\n(OER). Although IrO<sub><i>x</i></sub> is one of the benchmark\nacidic OER electrocatalysts, there are still challenges in designing\nhighly active and stable Ir-based electrocatalysts for commercial\napplication. Herein, a Ru-doped IrO<sub><i>x</i></sub> electrocatalyst\nwith abundant twin boundaries (TB-Ru<sub>0.3</sub>Ir<sub>0.7</sub>O<sub><i>x</i></sub>@ITO) is reported, employing indium\ntin oxide with high conductivity as the support material. Combing\nthe TB-Ru<sub>0.3</sub>Ir<sub>0.7</sub>O<sub><i>x</i></sub> nanoparticles with ITO support could expose more active sites and\naccelerate the electron transfer. The TB-Ru<sub>0.3</sub>Ir<sub>0.7</sub>O<sub><i>x</i></sub>@ITO exhibits a low overpotential of\n203 mV to achieve 10 mA cm<sup>–2</sup> and a high mass activity\nof 854.45 A g<sup>–1</sup><sub>noble metal</sub> at 1.53\nV vs RHE toward acidic OER, which exceeds most reported Ir-based OER\ncatalysts. Moreover, improved long-term stability could be obtained,\nmaintaining the reaction for over 110 h at 10 mA cm<sup>–2</sup> with negligible deactivation. DFT calculations further reveal the\nactivity enhancement mechanism, demonstrating the synergistic effects\nof Ru doping and strains on the optimization of the d-band center\n(ε<sub>d</sub>) position and the adsorption free energy of oxygen\nintermediates. This work provides ideas to realize the trade-off between\nhigh catalytic activity and good stability for acidic OER electrocatalysts.