Preparation, conversion, and comparison of the photocatalytic and electrochemical properties of ZnS(en)0.5, ZnS, and ZnO

In the present paper, we report the successful synthesis of a ZnS(en)(0.5) complex (en = ethylenediamine) with a cuboid morphology by a solvothermal method employing zinc powder and sulfur powder as the reactants in ethylenediamine and further conversion to ZnS and ZnO. Research showed that the morphology hardly changed after the ZnS(en)(0.5) complex had been converted into ZnS in a vacuum at 450 degrees C for 40 min and that nearly spherical ZnO grains with a mean diameter of 300 nm were obtained after the ZnS(en)(0.5) complex was oxidized in air at 650 degrees C for 40 min. Also, the experiments indicated that ZnS(en)(0.5), ZnS, and ZnO could degrade safranine T, an organic dye, under irradiation of 254 nm UV light and that ZnS had better photocatalytic degradation properties than ZnS(en)(0.5) and ZnO after irradiation for 30 min. The electrochemical studies showed that ZnS and ZnO had a stronger ability to promote electron transfers between hemoglobin (Hb) and the Au electrode than ZnS(en)(0.5) but had a weaker ability to accelerate electron transfers between catechol and the Au electrode than ZnS(en)(0.5). The possible mechanisms are discussed.