Preparation and investigation of a Ni–B-assisted SnO2–Sb anode for electrooxidation of phenol

Abstract

A Sb-doped SnO2 anode modified with Ni and B was fabricated by the sol–gel method. The effect of major operation parameters of electrode preparation, such as Ni content, B content, and calcination temperature, on the mineralization degree of phenol was investigated. Response surface methodology was used to optimize the experimental conditions and evaluate the association between various operation parameters. The morphology, crystal structure, and electrocatalytic performance of the prepared SnO2–Sb–Ni–B anodes were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), linear sweep voltammetry (LSV), and cyclic voltammetry (CV). The optimized sol–gel preparation ratio of citric acid, ethylene glycol, tin tetrachloride, antimony trichloride, nickel chloride, and boric acid was 650:200:100:6.5:0.5:2, and the calcination temperature of the electrode was 550 °C. The SnO2–Sb–Ni–B anode has the highest oxygen evolution potential of 1.63 V (vs. Hg2/Hg2SO4). The removal degree of phenol reached 58% within 2 h on the SnO2–Sb–Ni–B anode. The accelerated lifetime of the selected SnO2–Ni–B anode was 720 min, which was carried out in a 3-mol/L sulfuric acid solution with a current density of 500 mA/cm2.