Inefficient active site utilization of oxygen evolution reaction (OER) catalysts have limited the energy efficiency of proton exchange membrane (PEM) water electrolysis. Here, an atomic grid structure is demonstrated composed of high‐density Ir sites (≈10 atoms per nm2) on reactive MnO2–x support which mediates oxygen coverage‐enhanced OER process. Experimental characterizations verify the low‐valent Mn species with decreased oxygen coordination in MnO2–x exert a pivotal impact in the enriched oxygen coverage on the surface during OER process, and the distributed Ir atomic grids, where highly electrophilic Ir─O(II‐δ)− bonds proceed rapidly, render intense nucleophilic attack of oxygen radicals. Thereby, this metal‐support cooperation achieves ultra‐low overpotentials of 166 mV at 10 mA cm−2 and 283 mV at 500 mA cm−2, together with a striking mass activity which is 380 times higher than commercial IrO2 at 1.53 V. Moreover, its high OER performance also markedly surpasses the commercial Ir black catalyst in PEM electrolyzers with long‐term stability.

中文翻译：

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富氧覆盖位于 Ir 原子网格内，用于增强析氧电催化


析氧反应（OER）催化剂的活性位点利用效率低下限制了质子交换膜（PEM）水电解的能量效率。这里，展示了由高密度 Ir 位点（约每纳米 10 个原子）组成的原子网格结构2 ) 对活性 MnO 2–x支持介导氧气覆盖增强的 OER 过程。实验表征验证了 MnO 中氧配位减少的低价 Mn 物种2–x在 OER 过程中，对表面的富氧覆盖以及分布式 Ir 原子网格（其中高度亲电的 Ir─O）产生关键影响(II-δ)−键快速进行，引起氧自由基的强烈亲核攻击。因此，这种金属载体配合在 10 mA cm 电流下实现了 166 mV 的超低过电势−2 500 mA cm 时为 283 mV −2 ，以及比商业 IrO 高 380 倍的惊人质量活性2其电压为1.53 V。此外，其高OER性能也明显超越PEM电解槽中的商用铱黑催化剂，且具有长期稳定性。