Huang Shengnan, Lyu Guangshuo, Zhang Chuhui, Lin Chunye, Cheng Hefa
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Molecules. 2025 Aug 4;30(15):3258. doi: 10.3390/molecules30153258.
The precise synthesis of non-precious metal single-atom electrocatalysts is crucial for enhancing the yield of highly active reactive oxygen species (ROSs). Conventional oxidation methods, such as Fenton or NaClO processes, suffer from poor efficiency, high energy demand, and secondary pollution. In contrast, heterogeneous electro-Fenton systems based on cascade oxygen reduction reactions (ORRs), which require low operational voltage and cause pollutant degradation through both direct electron transfer and ROS generation, have emerged as a promising alternative. Recent studies showed that carbon cathodes decorated with atomically dispersed transition metals can effectively integrate the excellent conductivity of carbon supports with the tunable surface chemistry of metal centers. However, the electronic structure of active sites intrinsically hinders the simultaneous achievement of high activity and selectivity in cascade ORRs. This review summarizes the advances, specifically from 2020 to 2025, in understanding the mechanism of cascade ORRs and the synthesis of transition metal-based single-atom catalysts in cathode electrocatalysis for efficient wastewater treatment, and discusses the key factors affecting treatment performance. While employing atomically engineered cathodes is a promising approach for energy-efficient wastewater treatment, future efforts should overcome the barriers in active site control and long-term stability of the catalysts to fully exploit their potential in addressing water pollution challenges.
精确合成非贵金属单原子电催化剂对于提高高活性活性氧（ROS）的产量至关重要。传统的氧化方法，如芬顿或次氯酸钠工艺，存在效率低、能源需求高和二次污染等问题。相比之下，基于级联氧还原反应（ORR）的异相电芬顿系统，其运行电压低，通过直接电子转移和ROS生成实现污染物降解，已成为一种有前景的替代方法。最近的研究表明，用原子分散的过渡金属修饰的碳阴极可以有效地将碳载体的优异导电性与金属中心可调的表面化学性质结合起来。然而，活性位点的电子结构本质上阻碍了在级联ORR中同时实现高活性和高选择性。本综述总结了特别是2020年至2025年期间，在理解级联ORR的机制以及合成用于高效废水处理的阴极电催化中基于过渡金属的单原子催化剂方面取得的进展，并讨论了影响处理性能的关键因素。虽然采用原子工程化阴极是一种有前景的节能废水处理方法，但未来的努力应克服催化剂活性位点控制和长期稳定性方面的障碍，以充分发挥其在应对水污染挑战方面的潜力。
