Structure-controlled Synthesis Of Metal Bismuth And Its Composite Oxides And Their Photocatalytic Properties

The development of photocatalysts is an effective approach to solve energy crisis and environmental pollution which are the two big difficult problems in the world. The photocatalyst of TiO2 have been researched for years, however, it could be only excited by ultraviolet light and the utilization ratio of sunlight is relatively low, so it is especially important to develop novel visible-light-response photocatalysts. Among them, the series of bismuth compounds with the advantages of good visible light catalytic activity and stability have attracted more and more attention. For the excellent properties of the nano semiconductor materials and the influence of the microstructure on the properties, this thesis mainly studied the synthesized of different morphology nanocrystals of Bi and Bi4Ti3O4, and the properties under UV and visible light, discussed the link between the microstructure and the photocatalytic performance, revealed the important value of morphology control in the preparation of photocatalysts.This thesis used Bi(NO3)3·5H2O and ethylene glycol as the main raw materials, through adding different additives such as citric acid, trisodium citrate, cetyl trimethyl ammonium bromide(CTAB), oxalic acid and so on in reduction system, we synthesised Bi nanowires network, Bi monodisperse microspheres, microspheres, Bi nanoplates, Bi nanobundles, Bi hollow nanospheres and so on via solvothermal methods, and discussed the mechanism of different microstructure formation of Bi nanocrystals. The synthesized Bi nanowires network showed an excellent photocatalytic reduction efficiency of Cr(Ⅵ) under visible-light because of its uniform morphology, good dispersancy, larger specific surface area and good electronic conductivity.This thesis also discussed the synthesized of shape-controlled Bi4Ti3O12 semiconductor nanocrystal, through adjusting the quantity of mineralizer KOH and other experimental conditions such as reaction time, etc, the cross rod-shaped Bi4Ti3O12 nanocrystals is obtained via hydrothermal method, studied the photocatalytic reduction efficiency of methyl orange under visible-light over the Bi4Ti3O12 semiconductor nanocrystal photocatalyst, and the link between the morphology, particle size, specific surface area and the photocatalytic performance.