Influence of ZnS crystal morphology on adsorption-photocatalytic efficiency of pseudocrystal ZnS nanomaterials for methylene blue degradation

Crystal morphology of nanomaterials has a strong influence on its adsorption-photocatalytic activities. In this work, ZnS nanomaterials (NMs) with various shapes were synthesized by substitution reaction using ZnO as templates. The obtained ZnS NMs existed in the forms of ZnO pseudomorph with cubic sphalerite structure and were composed of numerous nanocrystal ZnS. Due to its porous nature, short nanotubes exhibited better adsorption performance for methylene blue (MB) than nanosheets or nanotubes. Their photocatalytic efficiency for MB followed nanosheets > short nanotubes > nanotubes. There was a higher exposure ratio of {100} crystal planes on nanosheets than that on nanotubes or short nanotubes. The density of Zn-S broken bond on the crystal plane followed D (100) >D (110) > D (111) . The higher exposure ratio of {100} crystal planes could not only endow ZnS nanosheets with a narrower bandgap, but also provide more sites to absorb reactants and trap electrons or holes.