Preparation Of Mg²⁺ Doping Cd_0.5Zn_0.5S Solid Solution And Its Properties Of Splitting Water Into Hydrogen

Hydrogen is an green and high secondary energy sources.It is broadly distributed in the universe. Water is the warehouse of hydrogen. Because solar energy is inexhaustible, photocatalytic water splitting by solar energy has been considered as one of the ideal hydrogen production processes. About three-quarters of area occupied by water.96%of the water store in the ocean. It will be very promising and meaningful to splitting saltwater into hydrogen from the practical application. In this thesis, we studied the preparation of Mg2+doping Cdo.5Zno.5S solid solution and its properties of splitting water into hydrogen. The research work is composed of two parts:1. The preparation of Mg2+doping Cdo.5Zno.5S solid solution and its properties of splitting water into hydrogen.Cdo.5Zno.5S and Mg2+doping Mg (m)/Cdo.5Zno.5S solid solution photocatalysts were prepared by a hydrothermal method. We investigated the hydrogen production activity of the catalyst under visible light (λ>420ran) using glucose as electron donor. Pt was deposited on Mg (m)/Cd0.5Zn0.5S in situ by photochemical deposition under visible light irradiation. The photocatalyst was characterized by X-ray diffraction (XRD), UV-Vis diffusive reflectance spectroscopy (DRS), BET specific surface area, electrochemical method, Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fluorescence spectra. It is found that Mg2+doping enhanced the properties of splitting water into hydrogen. When Mg2+doping content is0.4mole%, the photocatalyst exhibits the highest activity, and increased80%. The mechanism study shows that Mg2+doping enhanced the charge separation of photogenerated electrons and holes and extended the life of the light generated carriers. So the water splitting activity of the catalysts was improved.2. The properties of splitting saltwater and seawater into hydrogen of Mg2+doping Cdo.5Zno.5S solid solution.In this part, we studied the effect of electrolytes on the hydrogen activity and the properties of splitting seawater into hydrogen using glucose as electron donor. When the concentration of NaCl was2.0mol L-1, the property of splitting saltwater into hydrogen of Mg (0.4)/Cdo.5Zno.5S solid solution improved1.6times, the activity for H2evolution was increased by adding a little sylvine. When the system contained high concentrations of sylvine, the activity for H2evolution changed little. When the concentration of Mg2+was0.02mol L-1, the property of splitting saltwater into hydrogen of Mg (0.4)/Cd0.5Zn0.5S solid solution improved1.4times. But continued to increase the concentration of Mg2+, it reduced the activity for H2evolution. We also found that the change of the concentration and kind of anions (such as Cl-, Br" and SO42-) had little impact on the activity for H2evolution. In the seawater, the activity for H2evolution of Mg+doping solid solution was higher than in the pure water. It also had a certain stability in the seawater.