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 costeffective cathode materials for an efficient electro-Fenton process.

Automated summary

In this study, a facile self-sacrificial template route was used to synthesize heteroatom-doped porous biochar, which exhibited enhanced electrocatalytic activity for H2O2 production and Fe2+ regeneration. The biochar cathode achieved high H2O2 selectivity, efficient H2O2 activation rate, and effective degradation of various organic contaminants within a short time. The electro-Fenton system showed good stability and versatile applicability for organic pollutants remediation in different surface water matrices.