Overcome the trade-off in electro-fenton chemistry for in situ H2O2 generation-activation by tandem CoFe bimetallic single-atom configuration

Dual-atomic catalysts (DACs) demonstrated remarkable potential in addressing key challenges in electro-Fenton (EF) processes. In this study, we synthesized an EF DACs comprising both CoN4 and FeN4 sites, which was achieved a high H2O2 generation rate (1.68 mM (-1)h(-1)) and 100 % bisphenol A degradation efficiency via successive two-electron oxygen reduction and one-electron Fenton reactions (2e(-) ORR + 1e(-) Fenton). Our findings indicated that the single-atom nitrogen coordination of CoN4 and FeN4 sites plays crucial roles in regulating the adsorption of key intermediates of *OOH and *H2O2. The bimetallic sites independently regulated the binding energies of *OOH on CoN4 (pyrrole-type) for favorable H2O2 generation and its subsequent activation on adjacent FeN4 (pyridine-type). Thus, the dual-site engineering addresses the trade-off of in situ H2O2 generation-activation in EF chemistry, realizing high electron utilization efficiency and fast pollutant degradation toward efficient and sustainable water treatment.