ZnS is a kind of semiconductor photocatalytic material, which has great research value, but it also has the problems of easy recombination of photogenerated carriers and low utilization rate of sunlight due to wide band gap. Therefore, the modification of ZnS nanomaterials mainly focuses on improving the separation efficiency of electron (e-)-hole (h+) pairs and expanding light absorption. This article focuses on the modification of ZnS nanomaterials from three perspectives: the construction of the heterogeneous structure of the same compound, the formation of solid solutions and element doping.
We use high-temperature hydrothermal methods, using zinc powder and sulfur powder as raw materials, reacting in different concentrations of NaOH solutions to obtain ZnS nanomaterials with a two-phase structure, and then we pass XRD, SEM, TEM, and XPS testing methods. The obtained samples were characterized, and the test results proved the existence of two-phase structure in the samples. The experimental results show that the cubic phase is the main body, and the hexagonal phase nanosheets closely combined with the sample exhibit the best photocatalytic hydrogen production activity, indicating that the interface bonding mode, phase composition and phase transition process of the two phases have an effect on the crystallinity of the product. All effects will affect the photocatalytic activity of the material.
Two solid solution compounds of Mn-Zn-S were synthesized by a one-step hydrothermal method, cubic phase Mn0.05Zn0.95S and hexagonal phase Mn0.6Zn0.4S, and then we analyzed the crystal structure, morphology, and optical properties of the sample. The absorption properties were characterized, and the photocatalytic activity of the samples was evaluated by the experiments of visible light catalytic hydrogen production and visible light catalytic degradation of MB dye. The experimental results show that the cubic phase Mn0.05Zn0.95S sample has better photocatalytic activity than the hexagonal phase Mn0.6Zn0.4S sample.
In short, ZnS semiconductor, as an excellent photocatalytic material, is of great significance to the study of the expansion of its visible light response range. Phase structure control, solid solution, and heterogeneous element doping are all important ideas for the modification of semiconductor photocatalytic materials; MnS has special light absorption characteristics, and has similar crystal structure and lattice parameters to ZnS, and can form a solid solution with ZnS , To expand its light absorption and improve photocatalytic activity; Mn is an important transition metal ion, which can be used as a doping element to affect the light absorption of the parent substance, the separation of photogenerated carriers and other factors that affect the photocatalytic activity, thereby improving the material The photocatalytic activity of ZnS is also of great significance for the modification of ZnS.