In this work, the monometallic Pt and bimetallic Pt-Au nanoparticles-loaded mesoporous-assembled TiO2-SiO2 mixed oxide nanocrystal photocatalysts were investigated for hydrogen production from the photocatalytic Eosin Y-sensitized water splitting under visible light irradiation. A sol-gel process with the aid of a structure-directing surfactant was employed to synthesize the mesoporous-assembled TiO2-SiO2 mixed oxide with the TiO2-to-SiO2 molar ratio of 97:3 (i.e. 0.97TiO(2)-0.03SiO(2)), which was used as the base semiconductor photocatalyst. The Pt and/or Au loadings on the 0.97TiO(2)-0.03SiO(2) mixed oxide photocatalyst were achieved via a photochemical deposition method. The synthesized photocatalysts were systematically characterized by N-2 adsorption-desorption, XRD, UV-visible spectroscopy, SEM-EDX, TEM-EDX, and H-2 chemisorption analyses. The photocatalytic hydrogen production activity results revealed that the optimum monometallic Pt loading for a maximum photocatalytic activity was 1.25 wt.%, which corresponded very well to its maximum Pt dispersion. The increase in the Pt loading to a higher value of 1.5 wt.% unfavorably decreased the photocatalytic activity: however, the dilution of Pt by Au to attain the bimetallic 0.75 wt.% Pt-0.75 wt.% Au loading (with high total metal loading of 1.5 wt.%) was found to preserve the photocatalytic activity at an acceptably high level. (C) 2012 Elsevier B.V. All rights reserved.