Fenton catalysis represents the promising technology to produce super-active ·OH for tackling severe water environment pollution issues, whereas it suffers from low atomic efficiency, poor pH adaptability, and catalyst non-reusability in a homogeneous or heterogeneous system. Here, single-atom iron catalysis is creatively introduced to drive electrochemical ·OH evolution utilizing earth-abundant oxygen and water as raw materials. The atomically dispersed iron settled by defective three-dimensional porous carbon (AD-Fe/3DPC) with unique C, Cl unsaturated coordination can efficiently tune the multi-electron oxygen reduction process, enabling O₂-to-·OH conversion. The mass activity in ·OH production by AD-Fe/3DPC is almost two-orders of magnitude higher as compared to that by nanoparticular iron oxide catalyst. Meanwhile, the AD-Fe/3DPC electro-Fenton system exhibits fast elimination of refractory toxic pollutants, surpassing nanoparticular iron oxides in kinetic rate by 59 times or homogeneous Fenton by 10 times under similar experimental conditions. Experimental and theoretical results demonstrate that the remarkable enhanced mass activity of AD-Fe/3DPC in catalyzing O₂ to ·OH is contributed by the synergistic effects of the maximized catalysis of atomically dispersed iron and the unique unsaturated coordination environment. The AD-Fe/3DPC catalytic system is demonstrated to be pH-universal, long-term stable, and well recyclable, truly satisfying flexible, sustainable, and green application of wastewater purification. This study gives a new sight into local coordination modulation of single-atom catalysts for selective electrocatalytic oxygen reduction.

中文翻译：

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原子分散铁催化剂使分子氧对羟基自由基的高效电催化作用。

Fenton催化代表了一种生产超活性·OH的有前途的技术，可解决严重的水环境污染问题，而Fenton则具有原子效率低，pH适应性差以及在均相或非均相系统中催化剂不可重复使用的问题。在此，创造性地引入了单原子铁催化，以利用富含地球的氧气和水为原料来驱动电化学·OH的生成。通过具有独特的C，Cl不饱和配位的有缺陷的三维多孔碳（AD-Fe / 3DPC）沉积的原子分散铁可以有效地调节多电子氧还原过程，从而实现O ₂-OH的转化。与纳米颗粒氧化铁催化剂相比，AD-Fe / 3DPC产生·OH的质量活性几乎高两个数量级。同时，在类似的实验条件下，AD-Fe / 3DPC电芬顿系统表现出快速消除顽固性有毒污染物的能力，其动力学速率超过纳米颗粒氧化铁59倍，均质芬顿超过10倍。实验和理论结果表明，AD-Fe / 3DPC催化O _2的质量活性显着提高。·OH的产生是由于原子分散铁的最大催化作用和独特的不饱和配位环境的协同作用所致。事实证明，AD-Fe / 3DPC催化系统具有通用的pH值，长期稳定且可回收利用，真正满足了废水净化的灵活，可持续和绿色应用。这项研究为单原子催化剂的选择性电催化氧还原的局部配位调节提供了新视野。