C-N-Co-O Tuning Cobalt d-Band Center in Hierarchical Carbon Frameworks for High-Yield Electrosynthesis of H2O2 in Seawater

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Abstract
Electrocatalytic two-electron oxygen reduction reaction (2e--ORR) offers a green route for hydrogen peroxide (H2O2) synthesis, yet tailoring catalyst selectivity in complex environments like seawater remains a grand challenge. Herein, we report a composite of ZIF-67 and spherical graphite featuring a well-defined CoN2O3 coordination structure. This work elucidates a synergistic regulatory mechanism governed by N-to-O ligand exchange: the incorporation of high-electronegativity oxygen ligands, coupled with a reduced nitrogen coordination number, induces a significant downward shift of the cobalt d-band center. This electronic depletion not only optimizes the *OOH adsorption energy but, more critically, lowers the affinity of Co sites toward Cl-poisoning-a key challenge in seawater-based electrolysis. Theoretical and experimental analyses confirm that this electronic reconfiguration suppresses competitive Cl- adsorption and stabilizes the *OOH intermediate while preventing O-O bond cleavage. In simulated seawater (0.5 M NaCl), the catalyst delivers a H₂O₂ selectivity of ~71% within the 0-0.45 V vs. RHE potential range, exhibiting outstanding reaction kinetics (Tafel slope as low as 88.52 mV dec-1) and an exceptional high productivity (>230,000 mg gcat-1 h-1), approximately 4.5 times higher than leading neutral-media catalysts. Furthermore, it exhibits remarkable stability and tolerance to chloride poisoning for over 10 hours.
Funding Information
  • Natural Science Foundation of Heilongjiang Province (PL2024B005)
  • Fundamental Research Funds for the Central Universities (2024QN11027)
  • National Natural Science Foundation of China (21771047)

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