High performance duplex-structured SnO2-Sb-CNT composite anode for bisphenol A removal

Abstract

Abstract In this study, a duplex-structured SnO2-Sb-CNT composite anode (Ti/SnO2-Sb/SnO2-Sb-CNT) was fabricated using pulse electrodeposition technique. SnO2-Sb-CNT composite composed of 4–5 nm SnO2-Sb particles was synthesized via co-precipitation prior to the electrode preparation and characterized with BET and TEM. Characterization of Ti/SnO2-Sb/SnO2-Sb-CNT by FESEM, EDS, XRD, XPS, LSV, CV and EIS revealed that the novel duplex structured electrode had larger electroactive surface area and lower charge transfer resistance than conventional Ti/SnO2-Sb prepared by thermochemical decomposition, due to its more compact and rough surface. It also improved the electrochemical stability of Ti/SnO2-Sb/SnO2-Sb-CNT with a service lifetime up to 86 h. The oxygen evolution potential (OEP) of Ti/SnO2-Sb/SnO2-Sb-CNT was determined to be 2.2 V (vs Ag/AgCl). Bulk electrolysis of bisphenol A (BPA) was conducted to evaluate the electrocatalytic performance of the electrodes at various current densities (10–40 mA cm−2) and initial pH (3–11) of solution by determination of BPA degradation, total organic carbon (TOC) removal and mineralization current efficiency (MCE). Ti/SnO2-Sb/SnO2-Sb-CNT intended to adsorb more BPA molecules, which may contribute to its high current efficiency for electrochemical oxidation of BPA. The presence of humic acid (HA) could decrease the performance efficiency by inhibiting the adsorption of BPA by Ti/SnO2-Sb/SnO2-Sb-CNT. A mechanism is proposed to illustrate the enhanced degradation of BPA by Ti/SnO2-Sb/SnO2-Sb-CNT by synergistic adsorption and electrochemical oxidation.