Zhu, Yanping; Yang, Chenlu; Lu, Tongchan; Gan, Yizhen; Zhao, Hao; Chen, Yubin; Cheng, Qingqing; Yang, Hui

NANO ENERGY

2025, ,

Zhu, Yanping; Yang, Chenlu; Lu, Tongchan; Gan, Yizhen; Zhao, Hao; Chen, Yubin; Cheng, Qingqing; Yang, Hui

The electrochemical two-electron oxygen reduction reaction (2e-ORR) in acid offers a promising route for green synthesis of hydrogen peroxide (H2O2). Cobalt single atom material (CoN4-C) has ranked as an attractive catalyst towards 2e-ORR while still suffering the unsatisfactory selectivity owing to the strong *OOH adsorption on the Co center. Herein, we report an atmosphere-assisted pyrolysis method to precisely fabricate the CoN4-C single atom catalysts featured with varied Co-N bond length and Co spin states. Electrochemical analysis combined with operando electron paramagnetic resonance and in-situ X-ray absorption spectroscopy unravel the positive correlation between 2e-ORR selectivity and spin states. Density functional theory reveal that with the increase in spin state, the energy barrier associated with the cleavage of O-O bond in *OOH intermediate gradually increases while the desorption energy of *OOH decreases, thus promoting the 2e-ORR selectivity. As a result, the optimized CoN4-C catalyst exhibits the extraordinary 2e-ORR performance with high H2O2 selectivity (91.4 %), remarkable Faraday efficiency (91 %) and extremely stable H2O2 production rate (50 similar to 58 mg g(cat) h(-1)) over 30 h in a flow cell. This spintronic modulation strategy holds a promise for efficient electrosynthesis of H2O2 through 2e-ORR pathway.