| The degradation of organic pollutants using semiconducting photocatalytic materials has been widespread concern. Cadmium sulfide and titanium dioxide as two common semiconductors are a hot research. However, Cd S is prone to light corrosion reactions in the aqueous solution, and its photo-generated electron-hole easy recombination, which can lead to reduced its photocatalytic activity. The Ti O2 can only be excited the ultraviolet light, which limiting its application range. In order to improve the drawback of the above semiconductors. In this thesis, the Cu S doped Cd S catalysts were synthesized by direct coprecipitation; and carbon-coated Cd S(Cd S@C) and carbon-modified Ti O2 materials were preparated by one-step hydrothermal carbonization of glucose under mild conditions. Details are as follows:(1) Cu S doped Cd S materials(Cu S/Cd S) were prepared by a simple coprecipitation, their physical and chemical properties characterized by XRD, SEM, EDX, FT-IR and UV-Vis and their photocatalytic activity evaluated by degradation of methyl orange dye under visible light irradiation. The results showed that the antioxidant capacity of Cd S can be enhanced and its absorption in the visible region strengthened after the doping of Cu S. As a result, its photocatalytic activity was significantly improved in the visible light-triggered degradation of methyl orange.(2) Carbon-coated Cd S(Cd S@C) nanoparticles were conveniently prepared by a one-step hydrothermal carbonization method at temperature as low as 130 ?C. The prepared Cd S@C particles possess a smaller size, better dispersion and more uniform distribution than pure Cd S particles prepared under the same conditions. Furthermore, characterization results show the hydrothermal carbonization of glucose easily induces the prior formation of metastable cubic Cd S crystals. In addition, the carbonaceous species coated on the surface of Cd S expands the range of absorption light and slightly decreases the band gap of Cd S, as well as reduces the recombination of the photogenerated electron-hole pairs of Cd S and its photo-oxidative corrosion, which can improve the photocatalytic activity and stability of Cd S for the photo-oxidative degradation of methyl orange in aqueous solution under visible light irradiation.(3) The carbon modified Ti O2 photocatalysts were prepared at the temperature of 130 ?C by hydrothermal carbonization respectively using titanium tetrachloride and glucose as titanium and carbon sources, and their photocatalytic activity was evaluated by degradation of methyl orange and p-chlorophenol solutions under visible light. Characterization results showed that the organic carbon was mainly deposited on the surface of Ti O2 and small amount of carbon doped in Ti O2. The deposited carbon on the surface of Ti O2 can increase the specific surface area of TiO2, enhance its adsorption capacity for organic dyes, broaden the scope of the light absorption, which can lead to significantly improved photocatalytic degradation activity of methyl orange and p-chlorophenol. |
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