Inducing the surface enrichment of active noble metal can not only help to stabilize the catalyst but also modify the catalytic performance of the catalyst through electronic and geometric effects. Herein, we report the in situ surface enrichment of Ir on IrRu alloy during the oxygen evolution reaction (OER). The surface enrichment of Ir was probed by ex situ high-resolution transmission electron microscopy (HRTEM), in situ X-ray absorption spectroscopy (XAS), and electrochemical Cu stripping, leading to complementary characterizations of the dynamic reconstruction of the IrRu alloy during OER. Guided by the density functional theory (DFT), an IrRu alloy with low Ir content (20 wt%) was constructed, which displayed a low overpotential of only 230 mV to deliver an OER current density of 10 mA cm⁻² in 0.1 M HClO₄ solution and maintained stable performance for over 20 h. To investigate the practical application potential, a proton exchange membrane (PEM) water electrolyzer using the IrRu alloy as the anode catalyst was assembled, which required a low cell voltage of only 1.48 V to generate a current density of 1 A cm⁻².

中文翻译：

---

IrRu 合金上 Ir 的表面富集用于酸中高效稳定的水氧化催化

诱导活性贵金属的表面富集不仅有助于稳定催化剂，还可以通过电子和几何效应改变催化剂的催化性能。在此，我们报告了在析氧反应 (OER) 过程中 Ir 在 IrRu 合金上的原位表面富集。通过非原位高分辨率透射电子显微镜（HRTEM）原位探测 Ir 的表面富集X 射线吸收光谱 (XAS) 和电化学铜剥离，导致 IrRu 合金在 OER 过程中动态重建的互补表征。在密度泛函理论 (DFT) 的指导下，构建了一种低 Ir 含量 (20 wt%) 的 IrRu 合金，它显示出仅 230 mV 的低过电势，可在 0.1 M HClO 中提供 10 mA cm ^{-2的 OER 电流密度}₄溶液并保持稳定 20 小时以上。为了研究实际应用潜力，组装了使用 IrRu 合金作为阳极催化剂的质子交换膜 (PEM) 水电解槽，只需 1.48 V 的低电池电压即可产生 1 A cm ^-2的电流密度。