ZnO nanoparticle-functionalized WO3 plates with enhanced photoelectrochemical properties

Abstract

In this work, ZnO NPs-functionalized WO₃ vertical plate-like arrays were first fabricated on FTO with a hydrothermal process for WO₃ vertical plate-like arrays and an electrodeposition process for the functionalization of ZnO. The ZnO nanoparticles are preferentially loaded on the active points of WO₃ in the shape of a sphere about 10 nm. The samples were characterized by various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Photoelectrochemical properties were investigated by photoelectrochemical measures, such as linear sweep voltammograms, electrochemical impedance spectroscopy (EIS), intensity-modulated photocurrent spectroscopy (IMPS) and incident photon to current conversion efficiency (IPCE). The results show that the photocurrent of WO₃ increases from 0.88 to 1.23 mA cm⁻² at 1.2 V (vs. Ag/AgCl) after functionalized with ZnO. Furthermore, the lifetime of the electron–hole has been prolonged from 6.44 to 8.56 ms, but there is no decrease in the electron transport time. In this case, the enhancement of the photoelectrochemical performance is attributed to effective transfer of photo-generated holes so as to retard the recombination of electrons and holes.