Solvothermal Synthesis Of New Photocatalysts And Its Performance Study

Semiconductor photocatalysis is a comprehensive discipline which combines surface chemistry,material science,optics,electrochemistry, catalysis chemistry and environmental chemistry. The semiconductor materials can absorb the optical energy and produce the photo-induced electrons and holes which have strong reducing and oxidizability power as well, thus the direct and indirect reducing and oxidation reaction can be occurred at the surface of the catalyst. Among many semiconductor photocatalysts, TiO2 owing to its cheapness, nontoxicity, structural stability,and directly using solar energy is mostly frequently employed. However, the broad band gap and low quantum efficiency confine the development of TiO2 photocatalysts. Recently, it has been shown that the photocatalytic activity of TiO2 not only depends on the surface area,crystallinity,and morphology,but also depends on the exposed crystal faces. Our group have engaged in the research areas such as designing and development of photocatalyst for many years and thus getten much experience about the interaction of the photocatalyst's structure ,exposed crystal faces and their activities. Based on the quenstions of the photocatalytic area and the experience of our group, my works focus on the synthesis of photocatalysts with various morphologies and exposed faces through optimizing the synthesized conditions. The effect of morphology and exposed faces property to activity was explored in detail. The detail research work are listed as following:1.Alcoholthermal synthesis of highly active Bi2WO6 photocatalyst and photocatalytic activityHighly active Bi2WO6 visible photocatalyst with uniform sphere and high surface area was synthesized by alcoholthermal synthesis.The surface area of the sample was ten times more than the sample synthesized by solid state reaction.At the same time, the sample displayed high photocatalytic activity by the RhB degradation. 2.Hydrothermal synthesis of TiO2 microspheres with controllable structure and exposed {001} facets TiO2 microspheres with controllable structure and exposed {001} facets was synthesized by hydrothermal and using TiF4 and H2O. Based on the characterizations including XRD,FESEM and TEM,the external surface of the titania hollow microspheres was {001} facets.The titania hollow microspheres with exposed {001} facets display higher photocatalytic activity than P25 in selective oxidation of toluene. 3.Alcoholthermal synthesis of laminated microcrystal TiO2 with highly exposed {001} facetsLaminated microcrystal TiO2 with highly exposed {001} facets was synthesized by alcoholthermal synthesis.The surface area of the single-crystal TiO2 was higher than the reported literatures. Based on the characterizations including XRD,FESEM and TEM,the exposed ratio of the {001} facets as high as 95% was the highest of the reported literatures.The single-crystal TiO2 with exposed {001} facets display higher photocatalytic activity than P25 in selective oxidation of toluene.4.Alcoholthermal synthesis of single-crystal TiO2 with controllable structure and {001} exposed ratioSingle-crystal TiO2 with controllable structure and {001} exposed ratio was synthesized through TiF4 between benzal alcohol, alcohol, isopropanol, n-butyl alcohol and tert-butyl alcohol by alcoholthermal synthesis. Based on the characterizations including XRD, FESEM, TEM and XPS,we analyze the morphology, structure and {001} facets exposed ratio of various photocatalysts.The photocatalytic activity of various photocatalysts was tested by selective oxidation of toluene.