Preparation And Photocatalytic Activities For Hydrogen Evolution Of Cu Nanoparticles/Fluorine-doped Tin Oxide

Energy crisis and environmental pollution are two of the most serious problems that human are facing today.The appearance of photocatalytic technology provides a feasible way to solve the energy crisis and environmental pollution.However,because of the narrow light response range,poor stability and the recombination of photo-generated electrons and holes,the photocatalyst usually has low photocatalytic efficiency.Therefore,exploring highly efficient and stable photocatalysts become more important in the photocatalytic field.In this paper,we introduce the preparation and characterion of one new and highly efficient copper nanoparticles/fluorine-Doped Tin Oxide?Cu/FTO?and study its photocatalytic activity of hydrogen evolution.Tin Oxide?SnO₂?is n-type semiconductor material with high stability,and its intrinsic band gap is about 3.6eV.However,because of its broad intrinsic band gap,SnO₂ cannot fully use the visible light and its photocatalytic activity is low.So we need to modify it to increase the absorption of visible light.First,we synthesized FTO nanopowders by sol-gel method.By adjusting the content of fluorine,we got a series of FTO-Y?Y is the value of Sn/F molar rate,Y=1,3,5,7,9?nanopowders.Second,we successfully synthesized Cu/FTO nanocomposites by a simple hydrothermal method.By adjusting the content of copper,we got a series of Xwt%Cu/FTO?X is the value of copper mass fraction,X=7.4,13.7,19.2,24.1,28.4?nanocomposities.Moreover,the composition,microstructure and optical properties of photocatalysts are characterized by X-ray diffraction?XRD?,Fourier infrared spectroscopy?FTIR?,field emission scanning electron microscopy?SEM?,X-ray photoelectron spectroscopy,Photoluminescence spectroscopy?PL?,UV-visible diffuse-reflectance spectrum?UV-vis DRS?.Subsequently,the transient photocurrent and electrochemical impedance spectrum of photocatalysts were analyzed.At last,their photocatalytic properties of hydrogen evolution were studied.In the research of photocatalytic hydrogen evolution,on one hand,compared with the photocatalytic hydrogen evolution of different samples?19.2wt%Cu/FTO-Y,Y=1,3,5,7,9?,we determined the optimal content of fluorine?Y=5?.On the other hand,compared with the photocatalytic hydrogen evolution of different samples?Xwt%Cu/FTO-5,X=7.4,13.7,19.2,24.1,24.8?,we also determined the optimal content of copper?X=19.2?.We found that the photocatalytic hydrogen evolution rate of 19.2wt%Cu/FTO-5 is up to 1.122mmol·g^-1·h^-11 under visible light irradiation,which was far higher than the photocatalytic hydrogen evolution rate of 19.2wt%Cu/SnO₂(0.205mmol·g^-1·h^-1).Moreover,the photocatalyst exhibited excellent stability and repeatability during the recycling test of photocatalytic hydrogen evolution.In this paper,we also proposed the possible mechanism for enhanced photocatalytic hydrogen evolution of Cu/FTO photocatalysts under visible light irradiation.The presence of fluorine and copper nanoparticles can enhance the absorption of visible light and Cu nanoparticles can also improve the transfer efficiency of photogenerated electrons and inhibit the recombination of photo-generated electrons and holes,which is beneficial to improve the photocatalytic efficiency.