The accumulation of H2O2 on the surface of WO3 in the process of photoelectrochemical (PEC) water splitting leads to the decrease of photoactivity of WO3. To solve this problem, a thin layer of FeOOH acting as water splitting catalyst was coated on the active sites of WO3 surface. The WO3/FeOOH anode, with a deposition time of 20 min, showed a maximum photocurrent of 1.3 mA/cm(2) at 1.23 V vs reversible hydrogen electrode (RHE) under simulated solar illumination (AM 1.5G,100 mW/cm(2)). Furthermore, long time photostability of WO3 was achieved by depositing the FeOOH layer ascribed to its water oxidation ability to generate O-2 rather than H2O2. Interestingly, we found that a p-n junction between WO3 and FeOOH formed due to the different solvation effects on WO3 and FeOOH. The existence of p-n junction favored the transfer of holes from the WO3 to the FeOOH. (C) 2015 Elsevier Inc. All rights reserved.