Gold-nanoparticles/titanium dioxide (TiO2) composite structures that support localized surface plasmon resonances (LSPRs) in the visible region are prepared by thermal annealing thin gold films deposited on a TiO2 layer. Associated with the excitation of LSPRs, the prepared gold nanoparticle-loaded TiO2 could work as visible responsive photocatalysts to produce a greatly enhanced photocurrent density. By varying the initial gold film thickness, such gold nanoparticle-loaded TiO2 composite structures could be optimized to obtain the highest photocurrent generation efficiency. Furthermore, with the optimal plasmonic photocatalysts, we also show a considerably enhanced photoelectrochemical hydrogen generation from the platinum counter electrode. (C) 2013 Elsevier Ltd. All rights reserved.