Spatially Separated Electron Donor-Acceptor Dual Single-Atom Sites Coordinating Selective Generation of Hydroxyl Radicals via Fenton-Like Catalysis

Heterogeneous Fenton catalysis offers a promising alternative to traditional Fenton oxidation for water treatment as its wider operating pH range and high cyclic performance. However, designing catalysts that can activate H₂O₂ both actively and selectively to mineralize refractory pollutants remains challenging. Here, a state-of-the-art design principle of constructing spatially separated Fe-M (M denotes an oxophilic first-row transition metal) dual single-atom sites is developed for Fenton-like catalysis. This strategy enables accelerated redox cycles between the dual metal centers, leading to precise manipulation of Fe···O-O···M intermediate in H₂O₂ activation. This, in turn, aids the homolytic decomposition of H₂O₂ toward selective and efficient •OH generation. Taking Fe-Cu pairs as an example, the constructed dual sites outperform the individual Fe or Cu sites, demonstrating a higher activation selectivity (94%) for •OH production. Further benefitting from the electronic communications between Fe (electron acceptor) and Cu (electron donor), the SA-Fe-Cu-CN catalyst exhibited an effective H₂O₂ decomposition with 0.94 mm of •OH yielded within 50 min. Compared to the typical homogeneous system, the SA-Fe-Cu-CN/H₂O₂ system has higher mineralization capacities toward refractory pollutants and greater pH tolerance. The work provides a new strategy for the design of robust catalysts by creating spatially separated dual single-atom sites toward multi-reactant systems.