Hydrothermal/Solvothermal Synthesis and Photocatalytic Performance of ZnS Microspheres

ZnS microspheres were synthesized via hydrothermal/solvothermal method using Zn(Ac)2·2H2O and CH4N2S as reactants. ZnS was characterized by XRD, SEM and UV-Vis diffuse reflectance spectrum. The results showed that as-synthesized ZnS microspheres had zinc blende crystalline structure which was self-assembled by small ZnS nanoparticles. As for the photocatalytic degradation of phenol aqueous solution, ZnS microspheres synthesized in (CH2OH)2-H2O system revealed much better photocatalytic activity than that of ZnS synthesized in other solvent systems, and it kept high activity after cycling degradation for 3 times. The enhanced photocatalytic performance of ZnS microspheres could be attributed to the cooperation effect of the following three aspects: the smaller band gap (3.39 eV) being conducive to the absorption of photons, the more complete crystal structure to increase the number of active molecules, and larger specific surface area (19.4 m/g) being in favor of sufficient contacting between the reaction solution, and the catalyst. The intermediate products were oxalic acid, maleic acid and very little hydroquinone in photocatalytic degradation of phenol by ZnS microspheres.