Preparation Of Double Metal/Titanium Dioxide Nanoparticles By Using Block Bopolymer Micelles

As we all know, TiO2is good semiconductor material, but also has high photocatalyticproperties. Different structures of TiO2nanomaterials will lead to great differences in theirphotocatalytic properties. TiO2nanomaterials which were doped with noble metalnanoparticles is greatly improved in its photocatalytic properties, Therefore, it has become ahot spot and a significant challenge to prepare a novel structure of noble metal/TiO2nanomaterials on materials science. This paper aims to combine the self-assembledtechnology of block copolymer and the chemical properties of TiO2to synthesized noblemetal/TiO2nanocomposites with a novel structure.Firstly, self-assembly behavior between two kind of block copolymers P2VP-b-PEO andPS-b-P2VP and AgNO3inorganic component in tetrahydrofuran has been studied, whichfound that When the block copolymer and AgNO3was added to the tetrahydrofuran solventthey would spontaneously assemble into micelles, and the P2VP/Ag+is the core. Taking theUV light irradiation method to reduced Ag+to Ag and successfully prepared Ag nanoparticleswith a core-shell structure. The results show that the size of Ag nanoparticles can be regulatedby controlling the content of the block copolymer and ratio of the PVP and AgNO3. Moreover,as the copolymer shell can be dissolved in water or other organic solvents so that the Agnanoparticle can be stored in solution for a long time.Secondly, Using the Ag nanoparticles with core-shell structure as a sacrificial template toprepare Ag-Au Bimetallic Nanoparticles. Since AuCl4-/Au standard reduction potential(0.99Vvs standard hydrogen electrode) is higher than Ag+/Ag standard reduction potential(0.80Vvs standard hydrogen electrode), an electronic substitution reaction will occur when anappropriate proportion of HAuCl4is added to the Ag nanoparticles solution. Some Agnanoparticles will be consumed with the reduction of AuCl4+. Therefore Ag-Au nanoparticleswith special structure will be formed. The results showed that different structures of Ag-AuNanoparticles can be obtained with by changing the content of HAuCl4. When the HAuCl4content is small, it can get Ag-Au alloy nanoparticles. When the HAuCl4content is more,Ag-Au Nanoparticles with hollow structure can be obtained.Since the block copolymermicelles are used as a reaction vessel, a smaller size of Ag-Au Nanoparticles can be got. Combining the method of sol-gel, due to the interaction between Ti precursor and PEOmicro domains moreover occurring hydrolysis in the Hydrogen chloride solution, bimetallicAg-Au/TiO2composite nanomaterials can be prepared. By controlling the droppingof sol-geland the addition amount of sol-gel to adjust the morphology of bimetallic Ag-Au/TiO2composite nanomaterials. Through the degradation of methylene blue solution testing by UV-visible spectroscopy test using bimetallic composite nanomaterials Ag-Au/TiO2asphotocatalyst people can analyze the photocatalytic properties of bimetallic compositenanomaterials Ag-Au/TiO2. Experimental results show that comparing with single metalnanoparticlesas a photocatalyst Ag-Au/TiO2bimetallic composite nanomaterials have highcatalytic activity.