High efficiency two-step electrocatalysis boosted by dual-motif bridge Co-S-Mo for Heterogeneous Electro-Fenton: Enhanced H₂O₂ production and fluoxetine elimination synergistic mechanism

Heterogeneous electro-Fenton process is widely recognized as intensive in-situ strategy with environmental compatibility. However, the simultaneous elevation of H₂O₂ production and exploitation efficiency during electrocatalysis remains a challenge. Here, we propose an innovative dual-site catalyst (Mo_xCo_9xS_8yN_y; MCN) with Mo active motifs for enhanced two-electron oxygen reduction reaction and Co active motifs for enhanced reactive oxygen species generation to promote H₂O₂ generation and fluoxetine (FLX) degradation. As determined by Mo scaling and application performance, the optimal MCN catalyst provided at least 20 % increase in contaminant elimination within 30 min, reduced the reaction potential by over 1.4 eV, and diminished environmental exposure to toxic products. The optimal MCN@CF cathode efficiently removed approximately 96.7 % FLX and 55.1 % total organic carbon at a pH of 3 within 35 min. The critical dual-motif bridge Co–S–Mo mediated by S could disrupt the synergistic *O and *OOH binding energies, significantly penetrating the catalysis barriers. This work unravels the structural optimization evolution of non-single-site catalysts, providing new solutions to the refractory issues of wastewater decontamination.