Vertical aligned CuO nanowires (NWs) were synthesized by a simple and cost-effective thermal oxidation method. The NWs were decorated by Ag nanoparticles. Using the Ag nanoparticles decorated CuO nanowire arrays as photocathode, an enhanced photocurrent was achieved from photoelectrochemical water splitting under visible illumination with a photoelectrode energy-conversion efficiency of as high as 2.16%, due to the surface plasmon energy transfer from Ag nanoparticles to CuO NWs. (C) 2014 Elsevier B.V. All rights reserved.