Understanding photoelectrocatalytic degradation of tetracycline over three-dimensional coral-like ZnO/BiVO4 nanocomposite

Abstract

The coral-like BiVO4 was successfully constructed on ZnO nanorods grown on FTO substrates to reveal exceptional photoinduced charge migration kinetics as well as the underlying photoelectrocatalytic degradation process. The orderly ZnO nanorods array accelerated the separation of photogenerated carriers, while the three-dimensional coral structure of ZnO/BiVO4 nanocomposite increased the efficiency of light absorption and mass transfer, thus improving the photoelectrochemical properties. Fine interfacial contact between ZnO and BiVO4 led to the optimized photoelectrochemical performance with a photocurrent density of 0.29 mA/cm2 at 0 V vs. Ag/AgCl under visible light illumination (λ ≧ 420 nm), which was 3.2 times, 1.6 times of that of pristine ZnO and BiVO4. Moreover, the photoelectrocatalytic degradation efficiency of tetracycline from the ZnO/BiVO4 nanocomposite on was c. a. 84.5% and the main degradation paths were analyzed by LC-MS. Radical scavengers were employed to evaluate the capability to produce •O2− and •OH active species upon visible light illumination. This study elucidated the reaction mechanisms of the ZnO/BiVO4 nanocomposite during the photoelectrocatalytic degradation process.