Hydrogenated ZnO (H-ZnO) hierarchical nanorod arrays (HNRAs) with enhanced photoelectrochemical performance have been reported for the first time. The H-ZnO samples were obtained by annealing the ZnO nanorod arrays (NRAs) and HNRAs in hydrogen atmosphere at 350 degrees C for 60 min. The electrochemical impedance measurements indicate the donor density of H-ZnO HNRAs achieved 5.1 x 10(18) cm(-3), which is higher than those of other ZnO samples. These H-ZnO HNRAs yields an improved photocurrent density of 1.72 mA cm(-2) at 1.23 V vs. RHE, and the incident-photon-to-current-conversion efficiency (IPCE) values uniformly higher than 90% in the wavelength range from 300 to 370 nm, which are substantially higher than the pristine ZnO NRAs, ZnO HNRAs and H-ZnO NRAs. The ability to improve the photoelectrochemical properties of ZnO electrode materials may open up new opportunities for high-performance photovoltaic cells. (C) 2013 Elsevier B.V. All rights reserved.