Electronic tuning of SrIrO₃ perovskite nanosheets by sulfur incorporation to induce highly efficient and long-lasting oxygen evolution in acidic media

IrO₂ and RuO₂ are the currently available electrocatalysts towards oxygen evolution reaction (OER) in acidic media. However, their commercial applications are still restricted by sluggish kinetics and limited stability. Herein, we highlight a facile anion engineering strategy in monoclinic SrIrO₃ (M-SrIrO₃) perovskite nanosheets for boosting acidic OER performance. The resultant novel S-doped M-SrIrO₃ electrocatalyst delivers a low overpotential of 228 mV at 10 mA cm⁻² for 20 h to drive OER in 0.5 M H₂SO₄ electrolyte, which is superior to the benchmark IrO₂ and favorably rivals most the state-of-the-art Ir-based perovskite electrocatalysts. Notably, the surface Sr leaching is confirmed during OER process, resulting in surface reconstruction of Ir(O, S)_x amorphous layer. Theoretical calculations reveal that the S incorporation mitigates the strong binding of reaction intermediates, thus ultimately lowering the activation energy of OER kinetics. This protocol might offer an efficient approach of anion engineering in perovskites for various electrocatalysis.