▎ 摘　　要

The aim of the present work was to illuminate the catholyte-regulated catalytic oxidation performance and mechanism of the FeOOH-catalyzed heterogeneous electro-Fenton (Hetero-EF) system operating in a divided electrolytic cell. Depending on pH evolution with electrolysis time, the effect of the catholyte type on the H2O2 yield and current efficiency was investigated on an anthraquinone@electrochemically reduced grapheme oxide nanohybrid cathode. Based on the physicochemical characterization of the supported FeOOH nanoparticles, it was found that the Hetero-EF system exhibits the synchronous role of coupled adsorption and electrocatalytic oxidation for rhodamine B (RhB) degradation, with a higher apparent rate constant in MgSO4 catholyte and a higher mineralization rate in Na2SO4 catholyte. The catholyte-regulated catalytic oxidation mechanism was proposed according to radical scavenging experiments. In MgSO4 catholyte, the Hetero-EF process follows a classic Haber-Weiss mechanism mediated by the dissolved iron ions and surface iron species to generate center dot OH, while in Na2SO4 catholyte, the catalytic decomposition of H2O2 by surface iron species and the deactivation of Fe-III-OH center dot H2O2 complex to form HO2 center dot(O-2(center dot-)), center dot OH and ferryl species ( Fe-IV = O). X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy measurements revealed the desirable stability of Hetero-EF system after multiple reutilizations. (C) The Author(s) 2015. Published by ECS. All rights reserved.