N-doped graphene aerogel cathode with internal aeration for enhanced degradation of p-nitrophenol by electro-Fenton
Qian Tang1,2, Sijia Luo3, Hang Gao3
1Key Laboratory of Environmental Materials and Pollution Control, The Education Department of Jilin Province, Jilin Normal University, Siping, 136000, China. tangqian327@jlnu.edu.cn.
Abstract:
A columnar N-doped graphene aerogel (NGA) was successfully fabricated by one-step hydrothermal synthesis using L-hydroxyproline as reductant, N-doping, and swelling agent, and it was used as the cathode with internal aeration mode for the electro-Fenton degradation of p-nitrophenol. Owing to the stable solid-liquid-gas three-phase interface, more active defects, and modulated nitrogen dopants, the NGA cathode exhibited enhanced electrocatalytic activity. H2O2 could be continuously electro-generated via a two-electron oxygen reduction, and the yield of H2O2 was 153.3 mg·L-1·h-1 with the low electric energy consumption of 15.3 kWh kg-1. Simultaneously, the NGA cathode had better charge transfer capability with N-doping, which was conducive to the conversion of Fe3+/Fe2+. Under the optimal condition, nearly 100% removal of p-nitrophenol and 84% removal of TOC were obtained within 60 and 120 min, respectively. The NGA cathode also presented good stability and versatile applicability in different water matrices. Therefore, the NGA is a cost-effective cathode material in electro-Fenton system with adequate activity and reuse stabilization.
