Research On The Soft Chemistry Synthesis And Properties For Transition Metal Inorganic Composite Materials

Three composite compounds were prepared by soft methods(hydrothermal method,rheological phase reaction method and sol-gel method).The expected compounds were characterized by FT-IR,XRD,SEM,TEM,TG-DTA,UV-vis/DRS.The electrochemical properties of VO2/C(B)and Li1-xW0.01FePO4/C were investigated.The catalytic activity of the H3PW12O40/SiO2was tested through photodegradation of methyl violet.The obtained results are as follows:The nano-VO2(B)has been self-assembly synthesized by hydrothermal method using different templates,which may give them some interesting properties.The as-prepared samples were characterized by X-ray powder diffraction(XRD)?Thermogravimetric Analysis-Differential Thermal Analysis(TG-DTA)and scanning electron microscopy(SEM).The electrochemical properties of the samples were investigated.The results show that the hexadecyltrimethylammonium bromide(CTAB)(soft template)was used to obtain the VO2(B1)nanobelts.The flake graphite(hard template)was taken to get the VO2/C(B2)nanosheets.The VO2(B1)nanobelts has higher initial capacity to compare with VO2/C(B2)as an anode material.But the VO2/C(B2)nanosheets showed better cycling performance than that of VO2(B1)nanobelts.The nano VO2/C(B2)is a promising anode material for lithium ion battery application.Li1-xW0.01FePO4/C was synthesized by rheological phase reaction method.The XRD technology was used to analyze the structure of samples.The method of transmission electron microscope was taken to observe morphology of the particles.The electrochemical properties were also studied.The results showed that the non-stoichiometric Li1-xW0.01FePO4/C as a cathode material behaved excellent electrochemical properties to compare with that of pure LiFePO4.The initial discharge capacity of Li1-xW0.01FePO4/C arrived at 154 mAh/g at 0.1 C.The discharge capacity of Li1-xW0.01FePO4/C was retained at 139 mAh/g after 100 cycles.The Li1-xW0.01FePO4/C still behaved better performances at higher charge/discharge rate(1C).The possible reasons for Li1-xW0.01FePO4/C to behave outstanding electrochemical properties are discussed also.In order to remove aquatic organic dye contaminants utilizing the inexpensive and inexhaustible solar energy,the Keggin-type H3PW12O40 was loaded by the specific surface area SiO2 with the sol-gel method,and sensitized by H2O2 solution.The photocatalytic degradation of methyl violet by H3PW12O40/SiO2 under simulated natural light irradiation was investigated.At the same time,influences of the initial methyl violet concentration,the solution pH and the catalyst dosage on the photocatalytic degradation rate of methyl violet were also examined.The results demonstrated that initial concentration of methyl violet is 30 mg/L,catalyst dosage is 0.6 g/L and the pH is 2.5,the degradation ratio of methyl violet is as high as 92%after 2.5 h simulated natural light irradiation.