A Chlorine‐Resistant Self‐Doped Nanocarbon Catalyst for Boosting Hydrogen Peroxide Synthesis in Seawater

Developing seawater‐compatible hydrogen peroxide electroproduction technologies is crucial for advancing marine resource utilization in coastal regions. However, designing efficient and highly stable non‐noble metal catalysts for two‐electron oxygen reduction reaction in seawater environment remains a challenging task due to the corrosive and toxic nature of chloride ions (Cl‐). Herein, we present, for the first time, a novel nitrogen and oxygen self‐doped defect‐rich nanocarbon (NO‐DC700) catalyst, derived from silk fiber, which addresses these challenges with low toxicity, cost‐effectiveness, and high adaptability. The obtained NO‐DC700 catalyst demonstrates an impressive H2O2 production rate of up to 4997 mg L‐1 h‐1, a high Faradaic efficiency of 96.5%, and produces 4.3 wt.% H2O2 after 20 hours of stable operation, placing it among the highest‐performing catalysts reported in neutral electrolytes. Theoretical calculations reveal that NO‐DC700's superior 2e‐ ORR performance is due to the synergistic effect of graphitic nitrogen and C‐OH, which inhibits Cl‐ adsorption and promotes *OOH adsorption. Additionally, integrating 2e‐ ORR with Fenton‐like technology enables rapid degradation of organic pollutants and effective inactivation of seawater algae, offering significant potential for mitigating coastal eutrophication and red tide pollution. This work provides valuable insights into H2O2 electrosynthesis in seawater solution and promises advancements in ocean‐energy applications.