| Due to the potential application value of photocatalytic technology in degrading the organic pollutants in wastewater,it has an important research significance to prepare the low cost,good stability and high catalytic efficiency photocatalytic nanomaterials.The level of the photocatalytic efficiency could be limited because of the minimal light response range of single material catalyst,however,composite semiconductor photocatalysts occur the transfer of the electron-hole due to different levels under the light conditions which could improve the photocatalytic activity of semiconductor materials.This article aims to prepare the MoS2/SnO2 composite nanomaterials by two steps of hydrothermal method,and study its photocatalytic degradation efficiency to rhodamine B solution,and explore the possible growth mechanism of the MoS2/SnO2 composite materials and the photocatalytic mechanism at the same time.The specific content is as follows:The first part prepares MoS2 nanosheet by hydrothermal method firstly,and then synthesizes the MoS2/SnO2 composite material by hydrothermal method on the basis of the first step again,and the structure and morphology need to be characterized respectively;The photocatalytic degradation efficiency that MoS2 nanomaterials degrade rhodamine B solution is used to be a range parameter and conduct the range analysis to determine the influence order of preparation parameters,and the optimization of process parameters of MoS2 nanomaterials are obtained;At the same time,the result of single factor experiment about different[Sn4+]/[OH-]shows that when the[Sn4+]/[OH-]ratio is 1/7,the composites show composite structure morphology that SnO2 nanoparticles adhere to the layers of MoS2 nanosheets uniformly.The second part studies the impact on the growth of MoS2/SnO2 composite materials after adding SDS and PAM surfactants.The experimental results indicate that the added surfactants in the reaction process can provide a nucleation site,promote the crystal nucleation and also act as carriers of growth units with the different amount of added surfactant revealing effect of dispersant and surface growth inhibition.When the SDS content is 2.5%,SnO2 nanoparticles present a kind of gathered form growing in the external region of MoS2 nanoflower;When the PAM content is 0.00025%,SnO2 nanomaterials preferentially grow into rodlike structure on the surface of MoS2 nanosheets.The third part studies the photocatalytic efficiency about the prepared MoS2,MoS2/SnO2 and MoS2/SnO2 nanomaterials assisted by surfactant to rhodamine B solution under the same conditions,and the results show that the catalytic degradation efficiency of MoS2 and MoS2/SnO2 composite is 86.45%,94.88%respectively after 240 min of visible light irradiation,which indicates that composite materials has better catalytic activity than the single material;The catalytic degradation efficiency of the prepared MoS2/SnO2 samples assisted by 2.5%[SDS]/[Sn4+]and 0.00025%[PAM]/[Sn4+],which shows that the added surfactants can improve the efficiency of photocatalytic degradation to some extent;Photocatalytic cycle efficiency of MoS2/SnO2 composite results show that the composite materials still has good photocatalytic ability after circulating four times;Finally,the probable catalytic mechanism that the MoS2/SnO2 composite nanomaterials degrade the rhodamine B dye solution is discussed. |
