| The exhaustion of fossil energy and the increasing environmental pollution have become the two major problems of the human society. Therefore, how to develop and use renewable energy sources, such as solar energy, wind energy, etc, has become a hot research topic in the current research field. A lot of researches have been carried out and some meaningful results have been obtained. Therein, the photocatalytic technology has attracted much attention and been considered as an effective way to solve the above two problems due to its characteristics of environmental friendly, mild reaction conditions, simple operation process, sustainability and so on. The design and development of high efficient catalysts is the key of photocatalytic technology study. In recent years, metal sulfide nanomaterials have been considered as promising photocatalysts, and they have broad application prospects in photocatalytic hydrogen production and photocatalytic degradation. Herein, in this paper, SnS2 and MoS2 nanomaterials were choosed as the research objects and their synthesis and application in photocatalytic hydrogen production and photocatalytic degradation were studied systematically. And a series of interesting research results were obtained.1. Vermicular herzenbergite SnS2 nanoparticles were successfully synthesized in a facile hydrothermal process using SnCl4·5H2O and thioacetamide as raw materials, PVP as a coating agent and crystal growth modified agent. The size of the prepared SnS2 nanoparticles is about 3nm×6nm and they possess strong absorption ability to visible light, and specific surface area is larger (30.54 m2/g).2. The photocatalytic activity of Cr(Ⅵ) ion photoreduction reaction by the prepared SnS2 nanoparticles was discussed. It is found that the SnS2 nanoparticles have high catalytic activity for the Cr(Ⅵ) ion photoreduction reaction under visible light irradiation. Under its catalysis,99% Cr(Ⅵ) ions were transformed into Cr(Ⅲ) ions after 35 min of illumination. It is showed that as-prepared SnS2 nanoparticles are a visible light catalyst with great application potential, and as-prepared SnS2 nanoparticles are possible to be applied in the treatment of Cr(VI) pollutants.3. Multi-layered mesh-like MoS2 hierarchical nanostructure was successfully constructed on titanium plate in a one-pot hydrothermal process using Na2MoO4·2H2O and thiourea as raw materials, titanium plate as solid base and ethylenediamine as shape inducer. It is found that this hierarchical nanostructure is composed of few-layer MoS2 nanosheets, which possesses strong absorption ability to visible light and the very large specific surface area.4. The visible light photocatalytic hydrogen production activity of as-prepared MoS2 hierarchical nanostructure was explored using lactic acid as sacrificial agent. The results showed that the MoS2 hierarchical nanostructure is a highly efficient and stable catalyst for visible light hydrogen production. Under the optimal conditions, the photocatalytic hydrogen production rate is up to 240μmol·g-1·h-1. In contrast, common MoS2 nanoparticle film almost has no photocatalytic hydrogen production activity in the same reaction conditions. In addition, the effect of photocatalytic hydrogen production was studied as a function of concentration of sacrificial reagents, concentration of ethylenediamine, hydrothermal reaction temperature and hydrothermal reaction time. And we recognized that the multi-layered mesh-like MoS2 hierarchical nanostructure plays an important role in the process of photocatalytic hydrogen production. This role is mainly reflected in the following four aspects: (1) Larger specific surface area and a fast hydrogen diffusion channel is provided. (2) MoS2 nanosheets reunion is inhibited, more sulfur edge is exposed as reactive sites, and the photocatalytic activity is improved. (3)The reflection intensity of light is reduced, and the capture ability of catalyst to light is improved. (4) The transmission of photo electron and separation of electron hole pair have been promoted due to the characteristics of high length-diameter ratio and directional arrangement of nanosheets. |
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