Synthesis Of Cu_xZn_1-xS Micro/Nano Materials And Their Visible-Light Photocatalytic Performance

In this paper, Cu_xZn_1-xS micro/nanomaterials with different morphologies such asmicrospheres, microtubes, flower-like microspheres, were obtained by hydrothermaland solvothermal method. The photocatalytic activity of the samples wereinvestigated.Using CuCl₂·2H₂O, ZnSO₄·7H₂O and CH₃CSNH₂as raw materials, Cu_xZn_1-xSmicrospheres were synthesized by hydrothermal method. The crystal structures,morphologies and optical properties of the samples were characterized by XRD, SEM,FT-IR and UV-Vis, and their photocatalytic activity was studied. The results show thatthe Cu_xZn_1-xS microspheres have the same crystal structure of cubic phase ZnS, andthe crystal size of the samples gradually decreases with the increase of molar ratio x.The reaction temperature, reaction time, different molar ratio copper to zinc,surfactants and different copper and zinc salts have a great impact on morphology ofthe samples. FT-IR analysis shows that Cu0.03Zn0.97S is stabble, and no oxide isproduced owing to its oxidation. It has a good transmittance of the infrared light.UV-Vis analysis shows that the Cu_xZn_1-xS microspheres have strong absorption in theultraviolet region, however, the absorption in visible region enhanced with the copperand zinc molar ratio x increasing. Photocatalytic degradation of rhodamine B revealsthat the samples with different copper and zinc molar ratio have differentphotocatalytic effect, and the photocatalytic activity enhanced with the copper andzinc molar ratio x increasing.Using CuCl₂·2H₂O, ZnSO₄·7H₂O and CH₃CSNH₂as raw materials, Cu_xZn_1-xSmicrotubes were prepared by hydrothermal method. The samples were characterizedby XRD、SEM、TEM and UV-Vis techniques, and their photocatalytic activity wasstudied. The results show that most of diffraction peaks of Cu_xZn_1-xS coincide withhexagonal phase CuS, and its cell parameters are a=0.3796nm, c=1.6380nm. Theeffects of different conditions such as the molar ratio copper to zinc, reactiontemperature and reaction time on morphology of the samples were studied. TEManalysis shows that Cu_0.8Zn_0.2S microtubes are composed of the nanoflake with about35nm in width, and about80nm in length. UV-Vis analysis shows that Cu_xZn_1-xShave different degrees of absorption in the ultraviolet and visible region, andCu_0.8Zn_0.2S has a broad absorption peak at480nm. Photocatalytic degradation of rhodamine B reveals that the samples with different copper and zinc molar ratio havedifferent photocatalytic effect. When using Cu_0.8Zn_0.2S as photocatalyst, thedegradation rate of rhodamine B is up to98%under300W xenon lamp irradiation for120min.Using CuCl2·2H₂O, ZnSO₄·7H₂O and NH₂CSNH₂as raw materials,HOCH₂CH₂OH as solvent, Cu_xZn_1-xS flower-like microspheres composed ofnanoflakes were prepared by solvothermal method. The samples were characterizedby XRD, SEM, UV-Vis and AAS techniques, and their photocatalytic activity wasstudied. The results show that the crystal structure of the Cu_xZn_1-xS belongs tohexagonal CuS. The reaction time, reaction temperature, the molar ratio copper tozinc and sulfur sources have a great impact on the morphology of the samples.UV-Vis results show that Cu_xZn_1-xS in ultraviolet and visible region have a strongabsorption, and Cu_0.7Zn_0.3S has a broad absorption peak at560nm. The photocatalyticactivity studies show that the degradation of methylene blue is up to90%after40minirradiation under35W xenon lamp when using Cu_0.7Zn_0.3S as photocatalyst.Compared with the photocatalytic effect under xenon lamp and high-pressure mercurylamp irradiation, Cu_xZn_1-xS have higher activity and stronger catalytic ability in thevisible light region than that in ultraviolet region.