The Composition Of H_4xk_2xSn_2-xS_4+x/TiO₂ Composites With High Photocatalysis Degradation Capability For RhB

In this paper,a new kind of photocatalyst composite,H_4xK_2xSn_2-xS_4+x/TiO₂,was prepared successfully and the photocatalytic degradation mechanism of the material over RhB and other dyes in visible light was explored.H_4xK_2xSn_2-xS_4+x sheet substrate was first prepared by solvent thermal method,and then the tebubutyl titanate was supported on H_4xK_2xSn_2-xS_4+x through hydrolysis method,so H_4xK_2xSn_2-xS_4+x/TiO₂ composite was finally prepared.According to the AFM result,the thickness of H_4xK_2xSn_2-xS_4+x substrate material is about 6.4 nm.The SEM showed that TiO₂ was successfully loaded to H_4xK_2xSn_2-xS_4+x,XRD results showed that the TiO₂ was anatase type,FTIR,XPS and Raman characterization showed that TiO₂ and H_4xK_2xSn_2-xS_4+x was connected together by covalent bonding in the process of hydrolysis.Uv-vis DRS results showed that the absorption range of TiO₂extended from ultraviolet light to visible light,and PL spectra research showed that the composite rate of photohole-electron pairs was reduced,the active material life was improved,and the photocatalytic activity of H_4xK_2xSn_2-xS_4+x/TiO₂ composite material was significantly enhanced.Zeta potential characterization showed that the zero potential of the composite was 1.8,which indicates that the surface of the composite is electronegative over a larger p H range.The more electronegative the surface of the material was,the stronger the adsorption of cationic dye to the material was.BET showed that the specific surface area of H_4xK_2xSn_2-xS_4+x/TiO₂-1.0 was up to 114.49m_·²g^-1,which was significantly larger than that of pure TiO₂ and H_4xK_2xSn_2-xS_4+x,increasing the adsorption sites of dye molecules on the surface of catalyst materials,thus enhancing the photocatalytic performance.In order to explore the actual load capacity of titanium dioxide on the substrate of H_4xK_2xSn_2-xS_4+x in the composite material,ICP-OES test was conducted,and the results showed that the actual load capacity of TiO₂ was almost the same as the theoretical addition amount,indicating that the load effect of TiO₂ on the substrate of H_4xK_2xSn_2-xS_4+x was good.H_4xK_2xSn_2-xS_4+x/TiO₂ material was applied to photocatalytic degradation of RhB and other dye.Through the adsorption data and fitting analysis,the adsorption type of RhB over the composite material was Langmuir and the adsorption equilibrium could be reached within 10 min.The adsorption and photocatalytic degradation of RhB（20ppm）was carried out by using composites with different Sn/Ti ratio.Experimental data showed that H_4xK_2xSn_2-xS_4+x/TiO₂-1.0 composites exhibited a better photocatalytic degradation rate and the removal rate was 97.9%.At the same time,the composites also showed good degradation ability to other cationic dyes such as methyl orange and methyl blue,both of the removal rate are over 99%.Finally,the mechanism of photocatalytic degradation of RhB by composite materials was also investigated experimentally and the result showed the h⁺and·O^2-play a role in photocatalytic process.