N-doped three-dimensional carbon foam as binder-free electrode for organic pollutants removal by electro-Fenton in neutral medium

Abstract

Electro-Fenton in neutral medium has attracted more and more attention since it can relieve the costs of H2O2 storage and pH adjustment, which are the major disadvantages limiting the practical applications of Fenton reaction. The electrode with good performance for electrochemical H2O2 production from O2 in neutral medium is of great importance in electro-Fenton. Herein, the N-doped three-dimensional carbon foam (NCF) electrode was obtained by using melamine foam as precursor. The nitrogen functional groups and graphitization degree could be tailored by adjusting the carbonization temperature. NCF1000, the sample carbonized at 1,000 °C, presents the H2O2 selectivity of 81.9%, which is the highest among those of other NCFs. The H2O2 concentration in neutral medium on NCF1000 achieved 0.87 mmol L−1 at −0.6 V, which is 1.8, 2 and 2.6 times as much as those on graphite, carbon cloth and carbon felt. Using as cathode in electro-Fenton, NCF1000 exhibits the kinetic rate of 0.062 min−1 for phenol degradation, which is 4.1 times larger than that on graphite electrode. As well, the performance of NCF1000 shows no visible attenuation after ten times phenol removal experiments, demonstrating its good reusability. These results indicate the potential of NCF as a promising alternative for commercial carbon-based electrode in electro-Fenton.