Regulating Strain and Electronic Structure of Indium Tin Oxide Supported IrO Electrocatalysts for Highly Efficient Oxygen Evolution Reaction in Acid.

The development of proton exchange membrane water electrolysis is a promising technology for hydrogen production, which has always been restricted by the slow kinetics of the oxygen evolution reaction (OER). Although IrO is one of the benchmark acidic OER electrocatalysts, there are still challenges in designing highly active and stable Ir-based electrocatalysts for commercial application. Herein, a Ru-doped IrO electrocatalyst with abundant twin boundaries (TB-RuIrO@ITO) is reported, employing indium tin oxide with high conductivity as the support material. Combing the TB-RuIrO nanoparticles with ITO support could expose more active sites and accelerate the electron transfer. The TB-RuIrO@ITO exhibits a low overpotential of 203 mV to achieve 10 mA cm and a high mass activity of 854.45 A g at 1.53 V vs RHE toward acidic OER, which exceeds most reported Ir-based OER catalysts. Moreover, improved long-term stability could be obtained, maintaining the reaction for over 110 h at 10 mA cm with negligible deactivation. DFT calculations further reveal the activity enhancement mechanism, demonstrating the synergistic effects of Ru doping and strains on the optimization of the d-band center (ε) position and the adsorption free energy of oxygen intermediates. This work provides ideas to realize the trade-off between high catalytic activity and good stability for acidic OER electrocatalysts.