Controllable hydrothermal synthesis of hollow ZnS nanospheres: Morphological evolution mechanism and photocatalytic performance

ZnS hollow nanostructures have attracted much attention due to their special structural advantages and wide range of application. Exploring a convenient method for controllable synthesis of ZnS hollow nanostructures and clarifying the formation mechanisms are important prerequisites for subsequent performance regulation. In this article, we propose a facile method for controllable preparation of homogeneous ZnS hollow nanospheres and clarified the morphological evolution mechanism. ZnS hollow nanospheres with uniform size and good dispersibility were synthesized by adding PVP and excessive thiourea during the hydrothermal process. By systematically studying the influence of experimental parameters on the morphology, the influence diagram of thiourea and PVP on the product morphology was drawn. It is found that excess thiourea is the determining factor for the formation of hollow structures, and PVP plays a key role in the size uniformity and dispersion of the product. The formation mechanism is proposed in which thiourea serves as the reaction source and adsorbed molecule, while PVP serves as a dispersant, both of which worked together to the product morphology and size. The photocatalytic experiments indicate that hollow nanospheres with small size and good dispersibility exhibit a better photocatalytic degradation effect. This work elaborates on how the adsorption of thiourea molecules and the steric hindrance of PVP affect the grain aggregation and growth, which inspirational for the controllable synthesis of the required ZnS nanostructures and further research on their properties.