Pt, Rh2O3, NiO nanoparticles as cocatalysts were loaded on BYV solid solution photocatalysts by an impregnation method to promote photocatalytic activity for overall water splitting. The cocatalysts loading could enhance the photocatalytic activity significantly. The (photo)electrochemical measurements and HR-TEM, PL analyses revealed that the effect of cocatalysts acted as active sites depended on the efficient separation of photoinduced charge carriers as well as the reduction of the overpotential of 02 evolution. Among the cocatalysts in this study, Rh2O3 was found to give the highest photocatalytic activity. This is because, compared to Pt and NiO, Rh2O3 nanoparticles are able to not only reduce more overpotential of O-2 evolution, but also extremely promote the separation of electrons and holes. 0.5 wt% Rh2O3/BYV exhibited the highest photocatalytic activity for H-2 and O-2 evolution, reaching 104.4 mu mol/h and 50.9 mu mol/h, respectively. The present work will be useful to instruct cocatalyst loading for obtaining the photocatalysts with high photocatalytic activity for overall water splitting. (C) 2015 Elsevier B.V. All rights reserved.