The Preparation Of Binary Noble Metal Au-Ag Hybrid Nanoparticles Modified Semiconductor Photocatalyst And Its Photocatalytic Performance

With the increasing energy demand and the increasing shortage of energy,the development and utilization of new energy is particularly important,especially solar energy.Semiconductor photocatalysis technology has attracted the attention of researchers because of its advantages such as low energy consumption,simple operation,mild reaction conditions and environmental protection.However,most of the semiconductor photocatalysts have the defects of low visible light utilization and high electron hole recombination rate.Besides semiconductor photocatalysis,photocatalysis technology based on surface plasmon resonance of noble metal has been widely concered since it was found in 2008.In particular,due to the unique SPR effect of Au and Ag nanoparticles,plasmonic materials have become a new hotspot in the field of photocatalysis.Based on the above research background,we explored the controllable synthesis of binary Au-Ag nanoparticles and their composite with semiconductors.The properties of photocatalytic hydrogen production and reduction of 4-NP to 4-AP are studied.The main conclusions are as follows:Controllable synthesis of binary Au@Ag hybrid nanoparticles.In the second chapter,Au@Ag core-shell nanoparticles are prepared by the classical citrate reduction method.It is characterized by TEM and UV-Vis.Preparation and photocatalytic activity of Ag_xAu_1-x/ZIS.ZIS microsphere is prepared by the solvothermal method.Ag_xAu_1-x NPs are loaded on ZIS by 300 W mercury lamp,and then the Ag_x-Au_1-x/ZIS is obtained.SEM,EDX and other characterization methods shows that Ag_xAu_1-x NPs/ZIS samples are successfully prepared,and there is good interface contact between ZIS and Ag_xAu_1-x NPs.When the ratio of Ag/Au is 0.6/0.4,the optimal height of Schottky barrier of Ag_0.6Au_0.4/ZIS as well as excellent light absorption property lead to the significant enhancement of H₂ production ability.The H₂ production ability of Ag_0.6Au_0.4/ZIS is 7.1 times higher than that of ZIS under the same condition.Preparation and photocatalytic activity of Au@Ag NPs/TiO₂.Firstly,Au particles of different nano scale?15 nm and 25 nm?are prepared by the classical citrate method.Then,Au@Ag nanoparticles with different thickness of Ag layer are prepared by adjusting the amount of Ag NO₃ based on Au nanoparticles,sodium citrate and silver nitrate?Ag NO₃?.TiO₂ microspheres are prepared by solvothermal method.Au@Ag NPs is loaded on TiO₂ microspheres.SEM and HR-TEM showed that Au@Ag NPs is successfully compounded on TiO₂microspheres.The hydrogenation performance of 4-NP shows that 25 nm Au@Ag NPs/TiO₂ has better hydrogenation performance.