Fabrication of NiO quantum dot-modified ZnO nanorod arrays for efficient photoelectrochemical water splitting

NiO quantum dot (QD)-modified ZnO nanorod arrays with enhanced photoelectrochemical activity under simulated sunlight were prepared via hydrothermal and drop-drying methods. The results show an obviously decreases in the PL emission intensity and UV-to-Visible emission ratio in NiO QD-modified ZnO, indicating that the recombination of the photogenerated charge carrier is greatly inhibited in the heterojunction. Photocurrent density of the QD-modified nanorod photoanode reaches four times higher than its dark current density; the difference between the photo and dark current densities of QD-modified nanorod electrode is nearly two times higher than that of nanorod electrode. NiO QD-modified ZnO nanorods exhibit excellent photoelectrocatalytic activity owing to their large specific surface area and high separation efficiency of photogenerated electron-hole pairs. This study provides a promising strategy for fabricating highly efficient photoanodes for water splitting by configuring a Q-c-mposed p-n junction.