Znin <sub> 2 </ Sub> S <sub> 4 </ Sub> Photocatalyst Preparation And Photocatalytic Decomposition Of Hydrogen Sulfide

Ternary sulfides ZnIn2S4, CdIn2S4 and a series of CdxIn2S4-Zn1-xIn2S4 composite photocatalysts have been synthesized by hydrothermal method, Cd0.3In2S4-Zn0.7In2S4 composite photocatalyst was modified by doped transition metal ion Cu, Ni, Co. The effect of the preparation conditions, such as pH value, homogeneous precipitation reaction time, reactant concentration, hydrothermal reaction temperature and time were invstigated. The structure and physicochemical properties were characterized by X-ray diffraction, UV-Vis diffuse reflectance spectrum, X-ray photoelectron spectroscopy SPS and SEM-EDS. The performance of photocatalytic decomposition of H2S to produce H2 under visible light was studied.ZnIn2S4 photocatalysts synthesized by hydrothermal method could be indexed as a pure hexagonal phase, the absorption edge was 500 nm, The ZnIn2S4-160-24 showed the highest activity toward photocatalytic hydrogen production and the average rate of hydrogen evolution reached 764μmol/h-g. CdIn2S4 photocatalysts synthesized by hydrothermal method could be indexed as a pure cubic phase, the absorption edge was 550 nm, The CdIn2S4-160-1 showed the highest activity toward photocatalytic hydrogen production and the average rate of hydrogen evolution reached 303μmol/h-g. A series of CdxIn2S4-Zn1-xIn2S4 composite photocatalysts have been synthesized by hydrothermal method on the basis of CdIn2S4 and ZnIn2S4. All the photocatalysts were composite structure, the absorption edge shift to visible region and the band gap energy gradually reduced with the increasing of x value in CdxIn2S4-Zn1-xIn2S4. When x=0.3, the highest photocatalytic activity was observed on Cd0.3In2S4-Zn0.7ln2S4 with the rate of H2 evolution up to 590μmol/(h-g).Cd0.3In2S4-Zn0.7In2S4 composite photocatalyst doped with transition metal ion Cu, Ni, Co has been synthesized by hydrothermal method. When Cd0.3In2S4-Zn0.7In2S4 was doped with Cu/Ni/Co, the peaks of the sample were almost the same as the crystal structure of Cd0.3In2S4-Zn0.7In2S4 photocatalyst. The absorption edge of Cd0.3In2S4-Zn0.7In2S4 showed a red shift by Cu doping, however, a slight bule shift had been obsevered by Ni/Co doping. Doping Cu/Ni/Co ion directly affect the morphology of Cd0.3In2S4-Zn0.7In2S4, the shape of spheres presented to be irregular. The photocatalytic activity of doped photocatalysts had been improved as a result of the enhancement of the charge separation efficiency. The H2 evolution rates from the decomposition of H2S reached 1141μmol/(h·g),3319μmol/(h·g) and 2245μmol/(h·g) over Cu(2%)-Cd0.3In2S4/Zn0.7In2S4, Ni(5%)-Cd0.3In2S4/Zn0.7In2S4 and Co(7%)-Cd0.3In2S4/Zn0.7In2S4, which were higher than that of Cd0.3In2S4/Zn0.7In2S4.