The production of clean and renewable hydrogen through water splitting using photocatalysts has received much attention due to the increasing global energy crises. Prof. Jian Ru Gong and co-workers at National Center for Nanoscience and Technology have now demonstrated that a high efficiency of the photocatalytic H2 production from water under visible-light irradiation can be achieved over CdS-cluster-decorated graphene nanosheets, and the research paper entitled “Highly Efficient Visible-Light-Driven Photocatalytic Hydrogen Production of CdS-Cluster-Decorated Graphene Nanosheets” was published in JACS 2011, DOI: 10.1021/ja2025454.
The graphene-CdS nanocomposites reach a high H2-production rate of 1.12 mmol？h-1 at graphene content of 1.0 wt% and Pt 0.5 wt% under visible-light irradiation and an apparent quantum efficiency (QE) of 22.5% at wavelength of 420 nm. This high photocatalytic H2-production activity is attributed predominantly to the presence of graphene, which serves as an electron collector and transporter to efficiently lengthen the lifetime of the photogenerated charge carriers from CdS nanoparticles. Furthermore, the unique features of graphene allow photocatalytic reactions to take place not only on the surface of semiconductor catalysts, but also on the graphene sheet, greatly enlarging the reaction space. This work highlights the potential application of graphene-based materials in the field of energy conversion.
The research was financially supported by Chinese Academy of Sciences, National Basic Research Program of China from Ministry of Science and Technology, and National Natural Science Foundation of China.
(a) Schematic illustration of the charge separation and transfer in the graphene-CdS system under visible light; (b) Comparison of the visible-light photocatalytic activity of samples with different graphene content for the H2 production.