High H2O2 selectivity and enhanced Fe2+ regeneration toward an effective electro-Fenton process based on a self-doped porous biochar cathode

Cathode materials with high catalytic activity for H2O2 production and Fe2+ regeneration are essential to an efficient electro-Fenton process. Herein, we demonstrate a facile self-sacrificial template route to synthesize heteroatom-doped porous biochar. Owing to the created hierarchical porous structure and active defects, more generated oxygen functional groups (COOH/C–O–C) and modulated nitrogen dopants, the biochar cathode exhibits enhanced electrocatalytic activity. It achieves a high H2O2 selectivity (92%), facilitated Fe2+ regeneration, and an efficient H2O2 activation rate (82%). Various organic contaminants, including endocrine-disrupting chemicals, phenols, and antibiotics, can be effectively degraded with removal efficiencies of 98–100% within 15 min. The mineralization efficiencies achieve 83–100% with energy consumption of 0.87–1.07 kWh m−3. Moreover, the electro-Fenton system exhibits good stability and versatile applicability for organic pollutants remediation in different surface water matrices. This study offers valuable insights into the preparation of cost-effective cathode materials for an efficient electro-Fenton process.