Preparation And Performance Of Sandwich-Structured MoS₂-SnO₂-CF Composites

A novel sandwich structure MoS₂-SnO₂-carbon fiber composite flexible material was successfully synthesized by a simple two-step hydrothermal method.A double-layer heterojunction structure is formed by introducing extremely conductive carbon fiber substrate.This structure can accelerate the carrier migration rate and increase the electron-hole separation rate,which to enhance the photocatalytic activity.The results show that the photocatalytic degradation rate of this composite under visible light is 95%,which is much higher than that of the control groups.The main research contents of this paper include orthogonal experiment,single factor optimization experiment,control group experiment and exploration group experiment.The microstructure of the composites was characterized,also,the photocatalytic properties,electron-hole transport mechanism and reasonable growth process were discussed in detail.The mechanism of the improvement of the photocatalytic performance was analyzed according to the energy band structure of the composites.The morphology and photodegradation of the MoS₂-SnO₂-carbon fiber composite under the aid of the surfactant were studied.First of all,the preparation and characterization of SnO₂-carbon fiber precursor were discussed.The optimum reaction conditions of MoS₂-SnO₂-carbon fiber composites were studied by orthogonal test with three factors and four levels.The optimum experimental conditions were found out by means of range analysis.The intrinsic MoS₂-SnO₂-carbon fiber composites were prepared.The crystal structure,morphology,atomic composition,elemental spectra and specific surface area of the composites were studied by means of XRD,SEM,TEM,EDS,mapping,BET respectively.In the photocatalysis experiment,the 15mg/L concentration RhB solution was used as the dye which under the visible light irradiation of 100W-LED.After degraded in the visible light treatment,the morphology and structure of the cycle group experiment were studied by absorption spectrum,cyclic absorption spectrum,trapping agent experiment and so on.Single factor optimization experiments were carried out with the reaction time,which to explore the morphology pattern and performance comparison of MoS₂-SnO₂-carbon fiber composites in the optimization time range.There are comparative group experiments,including the preparation and morphology of composite MoS₂-SnO₂,composite MoS₂-carbon fiber,composite SnO₂-carbon fiber,carbon fiber substrate and the powder material MoS₂ and SnO₂.The light absorption spectrum of the contrast groups for all the experimental materials were exhibited,respectively.The relative concentration of photodegradation?c/c₀?,quantitative kinetic reaction,UV diffuse reflectance absorption spectrum and photoluminescence spectrum of the contrast groups were compared at the same time.Finally,the morphological structure model is established on the basis of the above microstructure characterization,and the energy band structure diagram is drawn which to analyzes the mechanism of the performance improvement caused by the heterojunction structure.At last,three groups of experiments were introduced,which explained the reason of using SnO₂-carbon fiber as precursor,the necessity of hydrophilic treatment of carbon fiber,and data of the photodegradation experiment of composites with different dyes,respectively.The preparation,characterization and properties of MoS₂-SnO₂-carbon fiber composites assisted by surfactants were studied.The SDS was used as anionic surfactant,and the CTAB was used as cationic surfactant.In this paper,the preparation process of adding two kinds of surfactants was introduced,moreover,the pattern of microstructure of the products prepared at different concentration specific surfactants(active agent/[Mo⁴⁺]=1%,2.5%,5%)and the reasonable explanation of the improved mechanism of photocatalytic activity were discussed detailly.Finally,the relative concentration of photocatalytic degradation?c/c₀?,quantitative kinetic reaction diagram and UV diffuse reflectance absorption spectrum analysis were used to compare the performance,degradation efficiency,and the absorption range respectively,which to select the surfactant with optimal concentration ratio.