In the past decade, the serious world’s energy and environmental crisis make people pay more attention on the development of sustainable carbon-neutral energy. As an efficient energy carrier with the highest energy density values per mass of 140 MJ/kg, hydrogen represents a green fuel of the further. The current main production of hydrogen comes from the petroleum industry, which consume the nature resources and generate CO2. Thus to generate hydrogen by photocatalysis(PC) or photoelectrocatalysis (PEC) from water splitting under solar light irradiation is anticipated as promising further technology to solve the energy crisis. In another hand, the photocatalysis or photoelectrocatalysis can also be used to degradation of inorganic/organic pollutant, which also provide a new route to solve the environmental crisis.
In this work, we report for the first time the composite thin films of GO, CdS quantum dots and ammonium metatungstate ((NH4)6H2W12O40, denoted as H2W12) which were fabricated by the layer-by-layer (LbL) self-assembly method, and an in situ photoreduction protocol was adopted to convert GO to rGO due to the photocatalytic activity of H2W12. The composite film was characterized by techniques such as UV-Vis spectra, XPS, and AFM. The composite film showed high photoelectronic response under the illumination of sunlight. Both current–voltage curves and photocurrent transient measurements demonstrated that the photocurrent response of the rGO–CdS–H2W12 composite film was enhanced five-fold compared with CdS film. This can be attributed to the photoinduced electron transfer between CdS, H2W12 and rGO, which promotes the charge separation efficiency of CdS. The introduction of GO enhanced the charge separation and transportation. More importantly, various pollutants can be treated as electron donors, and can thus be degraded and produce hydrogen at the same time, at a low bias voltage under the irradiation of solar light.
This work has been published on the Phys. Chem. Chem. Phys., 2014, 16, 26016-26023. The related research work was supported by the National Natural Science Foundation of China (No. 21371173, 51402298 and 21207133) and China Postdoctoral Foundation (No. 2014M550846).
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