The nanoflower-structured WO3 sensitized with CdS nanoparticles (CdS/WO3) was prepared on etched Ti substrate using a solvothermal method. The WO3 nanoflowers were composed of many nanoflakes, which endowed WO3 with large specific surface area and good charge carrier migration capabilities. CdS nanoparticles were deposited on the surfaces of the nanoflakes. Heterojunction electric fields were formed on the interface of CdS/WO3, resulting in the enhancement of the separation efficiency of the photogenerated electrons and holes and thus the promotion of the photoelectrochemical cathodic protection performance. WO3 can store electrons, leading to a time-delay cathodic protection for the coupled metal in the dark. (C) 2016 The Electrochemical Society. All rights reserved.