A compact and nanoporous structured WO3 film was prepared by electrodeposition. For a nanoporous structured WO3 film, polystyrene (PS) beads with a size of 320 nm were used as the template. The PS beads were completely removed by the thermal treatment, affording inverse opal WO3 films. For the inverse opal WO3 film (1 min), the highest photocurrent density (1.75 mA/cm(2) at 1.5 V versus sat. Ag/AgCl) was achieved and exhibited a superior PEC performance, up to similar to 46% compared to the compact WO3 film. (C) 2015 The Electrochemical Society. All rights reserved.