Study On The Synthesis Of SnWO₄/g-C₃N₄ Photocatalyst And Its Photocatalytic Activity Driven By Visible Light Irradiation

Photocatalysis as an efficient and environmental-friendly way to manage pollution has received extensive attention in recent years.G-C₃N₄ is a very potential catalytic materials because of its many advantages,sach as non-toxic,stable chemical properties and low cost.Nevertheless,the high recombination rate of photo-generated electron-hole pairs and low utilization of sunlight are two main issues limiting the significant photocatalytic efficiency of g-C₃N₄.In order to improve its photocatalytic activity in visible light,we considered to combine g-C₃N₄ with another traditional narrow band semiconductor catalyst SnWO₄.Using g-C₃N₄,Na2WO₄ and SnCl2 as the raw materials,the visible-light photocatalyst SnWO₄/g-C₃N₄ was synthesized by solvothermal process.The prepared photocatalysts were characterized by XRD,SEM,TEM,UV-vis DRS and BET surface area analysis.The preparation conditions of the SnWO₄/g-C₃N₄ photocatalysts with better visible light photocatalytic activity were screened through the degradation of methylene blue,and the influencing factors of photocatalytic degradation of methylene blue,eosin B and malachite green and the reuse performance of the photocatalysts were also investigated.The results of this study show that:?1?The optimum synthesis condition of SnWO₄/g-C₃N₄ was selected as:solvothermal synthetic temperature-180?,solvothermal holding time =12 h,the pH value of solvothermal precursor =7,and n?SnWO₄?:n?g-C₃N₄?=0.1:1.The degradation rate methylene blue compared with pure g-C₃N₄ and pure SnWO₄ increased by 91.9%and 46.7%.?2?The SnWO₄/g-C₃N₄ photocatalyst has splendid photocatalytic activity to photodegrade methylene blue,eosin B and malachite green.The decolorization rate could reach about 94.2%after visible-light illumination for 180mins,when the initial concentration of methylene blue was 15mg/L,the catalyst dosage was 1.0g/L;The degradation rate of 20mg/L eosin B could amount to 99.9%within 180 mins using 0.6g/L compound catalyst;And the degradation rate of 20mg/L malachite green can reach about 88.7%within 180 mins using 1.5g/L compound catalyst.?3?NaCl inhibited the degradation of methylene blue,eosin B and malachite green.?4?The SnWO₄/g-C₃N₄ photocatalyst has excellent photocatalytic activity to photodegrade methylene blue,eosin B and malachite green after 5 times of repeated use.?5?Photocatalytic degradation of methylene blue,eosin B and malachite green accord with the first-order reaction kinetics model,and the apparent reaction rate constant decreased with the increase of initial concentration of solution.This topic research will further broaden the research field of graphite phase nitride carbon and tungstate photocatalyst,and the research result has a certain theories guides and realistic meaning to the treatment of dye wastewater and other refractory organic pollutants.