Synergistic Single-Atom and Clustered Cobalt Sites on N/S Co-Doped Defect Nano-Carbon for Efficient H2O2 Electrosynthesis

Non-noble-based single atomic catalysts have exhibited significant potential in electrochemical production of H₂O₂ via two-electron oxygen reduction reactions (2e^- ORR). However, constructing highly efficient and acid-resistant catalysts remains a challenge but significant. In this work, fullerene (C₆₀) with abundant pentagonal inherent defects was employed as a carbon substrate to synthesize defect-rich nanocarbon electrocatalysts doped with NSCo single atoms and accompanied by metallic Co nanoparticles (CoSA/CoNP-NSDNC) for the first time. The electrochemical experiments demonstrate that the active sites of CoSA/CoNP-NSDNC are formed through the synergistic interaction between NSCo single atoms and Co nanoparticle clusters embedded within the carbon framework. The obtained CoSA/CoNP-NSDNC catalyst exhibits an onset potential as 0.72 V versus RHE and achieves up to 90% H₂O₂ selectivity over a wide potential range of 500 mV. Moreover, the as-obtained CoSA/CoNP-NSDNC configured as the cathode in a self-assembled flow cell under acidic conditions achieves a high H₂O₂ production rate of 4206.96 mmol g_cat⁻¹ h⁻¹ with a Faraday efficiency of ∼ 95% and exhibit ultra fast degradation of organic pollutants. This work focuses on the synergistic effect of non-noble metal nanoparticles, metal single-atom sites, and topological defects on the 2e^- ORR process, which provides a new direction for designing carbon-based catalysts for efficient H₂O₂ electrosynthesis.