Proton-gated multisite concerted proton-electron transfer-like pathway in a dual-atom framework for selective water purification

Abstract

Precise oxidant activation is essential for advanced water treatment but is often limited by radical quenching and low oxidant efficiency. Peroxymonosulfate (PMS) is promising; however, directing O-O cleavage towards non-radical pathways requires tightly coupled proton‒electron transfer, which is rarely achieved in heterogeneous catalysts because of spatially mismatched active sites. Here, we report a Co/Ni dual-single-atom metal–organic framework (MOF), in which atomically dispersed Co/Ni sites and adjacent noncoordinated -NH groups form a preorganized local microenvironment for PMS activation. Combined experimental and computational evidence suggests that Ni-assisted electronic coupling facilitates charge redistribution towards Co-bound PMS, while adjacent noncoordinated -NH motifs provide a local proton-relay environment, collectively favoring an MS-CPET-like pathway. This pathway promotes heterolytic O–O cleavage and the formation of a high-valent cobalt–oxo intermediate (Co(IV) = O). Consequently, the catalyst delivers a normalized rate constant of 6.2 × 103 M−1 min−1 with more than 95% PMS consumption under the tested conditions. Remarkably, the system operates stably for more than 1000 h under continuous flow, with a treatment capacity exceeding 1000 L. This work demonstrates a promising strategy for achieving non-radical-dominated and sustainable water purification through electronic regulation and -NH proton coupling within the framework of bimetallic MOFs. The authors report a Co/Ni dual-atom framework that couples local proton delivery with electron regulation to activate peroxymonosulfate, enabling selective pollutant removal and stable continuous-flow water treatment.