To efficiently convert solar energy into chemical energy by artificial photosynthesis, we need to develop visible-light-responsive photocatalysts with a high quantum efficiency (QE). Here we report that an artificial photocatalyst (Pt-PdS/CdS) can achieve a QE up to 93% in photocatalytic H-2 production in the presence of sacrificial reagents under visible light irradiation, and is very stable under the photocatalytic reaction conditions. The extremely high QE could be achieved by loading as low as 0.30 wt% of Pt and 0.13 wt% of PdS as cocatalysts on CdS. (C) 2009 Elsevier Inc. All rights reserved.