In suit synthesis of Fe3O4 on carbon fiber paper@polyaniline substrate as novel self-supported electrode for heterogeneous electro-Fenton oxidation

Abstract

Abstract In this study, a self-supported CFP@PANI@Fe3O4 cathode with three-layer structure was fabricated using a two-step synthetic route and characterized to reveal the morphology, composition and electrochemical performance of the novel electrode. The as-prepared CFP@PANI@Fe3O4 electrode showed enhanced electrocatalytic performance for p-nitrophenol degradation in electro-Fenton (EF) process with boron-doped diamond (BDD) electrode as anode. The results showed that for CFP@PANI@Fe3O4 cathode, 20\u202fmg\u202fL−1 of p-nitrophenol was almost degraded in 60\u202fmin and the removal efficiency of total organic carbon (TOC) was 51.2% under the condition of applied current density 5\u202fmA\u202fcm−2 and initial pH 3.0, which accompanied with more effective mineralization current efficiency (MCE) and less energy consumption (EC) compared with CFP and CFP@PANI electrodes. This enhancement was due to the increased electrocatalytic ability of in suit grown Fe3O4 on the surface of conductive substrates. Further investigation indicated that the fabricated electrode retained a high level of stability after consecutive runs. The reasonable reaction mechanism of p-nitrophenol was finally proposed according to the analysis of radical trapping experiments and fluorescence spectra, in which the hydroxyl radical (·OH) was deemed to the primary active oxidants. This work demonstrates the enormous potential of establishing an EF system with an efficient self-supported cathode based on in suit Fe3O4 immobilization for environmental remediation.