Fabrication of Co-Doped ZnO Photoanode by Liquid Phase Deposition for Photoelectrocatalytic Degradation of Ofloxacin under Visible Light

Abstract

A cobalt (Co)-doped ZnO film electrode was facilely fabricated via a one-step liquid phase deposition process. It was found that many rhombus-like nanoparticles with wurtzite crystal structure were uniformly deposited on the surface of electrode, and the doped Co in the film was at bivalent state. Moreover, the as-deposited film was investigated by UV-visible diffuse reflectance spectroscopy, photoluminescence, and cyclic voltammetry. Under visible light illumination, the Co-ZnO film electrode showed higher photocurrent than pure ZnO film electrode. It was explored as photoanode for visible light-driven photoelectrocatalytic (PEC) degradation of ofloxacin (OFL). The amount of Co doped in ZnO film for PEC degradation of OFL was optimized as 7.5% (at.%). Compared with other degradation methods such as direct photolysis, photocatalysis and electrochemical oxidation, PEC exhibited the highest degradation efficiency for OFL which reached 86.7% after 6-h treatment. Furthermore, the major intermediate products during the PEC process of OFL were identified by high-performance liquid chromatography-mass spectrometry; and a possible degradation mechanism for OFL on the Co-ZnO film electrode was proposed.