Development of a high-efficiency monolithic carbon-based cathode for electro-Fenton water treatment

The development of efficient and stable cathode materials for in-situ hydrogen peroxide (H₂O₂) production via the two-electron oxygen reduction reaction (2e⁻ ORR) is pivotal for advancing electro-Fenton technology. Herein, a monolithic carbon-based cathode (CM-1000) was fabricated through direct carbonization of a thermosetting phenolic resin and employed as an efficient and durable electrode for H₂O₂ production in electro-Fenton system. The self-supporting and binder-free architecture effectively eliminates interfacial resistance and catalyst detachment issues commonly associated with catalyst-coated electrodes, thereby ensuring stable catalytic activity and structural integrity. To benchmark its performance against common carbon-based materials, the CM-1000 cathode achieved a H₂O₂ production rate of 1.82 mmol·L⁻¹·h⁻¹ under optimal conditions (current 100 mA, pH 3), significantly surpassing conventional graphite bar (0.32 mmol·L⁻¹·h⁻¹) and carbon felt (1.07 mmol·L⁻¹·h⁻¹). Such performance stems from a synergistic effect of a highly aromatic carbon matrix enriched with stabilized carbonyl ( C = O ) and etheric (C-O-C) functional groups, coupled with a well-developed porous architecture (BET surface area 407.52 m²·g⁻¹). In the electro-Fenton system, CM-1000 achieved complete degradation of dimethyl phthalate (DMP) within 45 min (kₐₚₚ=0.100 min⁻¹), while maintaining stable 100% degradation efficiency and consistent H₂O₂ production performance over seven consecutive cycles. These results demonstrate the great potential of the monolithic carbon-based cathode for practical electro-Fenton water treatment.