Overpotential regulation of vanadium-doped chitosan carbon aerogel cathode promotes heterogeneous electro-Fenton degradation efficiency

This work aimed at exploring the effect of optimal overpotential discrepancy between two-electron oxygen reduction reaction (OP2eORR) and metal reduction reaction (OPMRR) of the cathode on electro-Fenton (EF) system performance, and proposing strategy to eliminate overpotential discrepancy. Therefore, series of vanadium-doped chitosan carbon aerogel (xCCA-V) cathodes were fabricated by controlling graphitization degree. With carbonized temperature of 900 degrees C, the OP2eORR of the 900CCA-V was -0.5 V vs. SCE, the same with the OP for vanadium reduction reaction (OPVRR). This identical OP of the 900CCA-V endowed excellent EF performance, with ciprofloxacin removal of 98.1%, and TOC removal significantly increased by 41.8% compared with Ferrum-doped CCA (900CCA-Fe). Density functional theory calculation revealed efficient active sites for H2O2 adsorption on the 900CCA-V surface. Degradation pathways of ciprofloxacin and intermediates toxicity were determined. This work provides inspiration for developing strategy for overpotential regulation and design novel and efficient cathodes for enhancing EF performance.

Automated summary

This work aims to explore the effect of optimal overpotential discrepancy between two-electron oxygen reduction reaction (OP2eORR) and metal reduction reaction (OPMRR) of the cathode on electro-Fenton (EF) system performance, and propose a strategy to eliminate overpotential discrepancy. The research demonstrates that cathodes with the same overpotential as the desired reaction exhibit superior EF performance.