Preparation And Photocatalytic Properties Of BiOX Based Composite Heterojunction Powder And Film Materials

In recent years,energy shortage and environmental pollution have brought serious impact on people’s lives.Developing renewable resources is the main task at present.Semiconductor photocatalysis technology has attracted wide attention in recent years because of its simplicity,convenience and good effect.Semiconductor photocatalyst has also become one of the most promising photocatalysts in the field of photocatalysis.Bismuth halide oxide(BiOX,X=Cl,Br,I)has attracted extensive research interest because of its unique layered structure,indirect transition mode,suitable banded structure,high chemical and optical inertia,non-toxic,cost-effective and high corrosion resistance.However,it cannot be widely used because of its defects such as easy separation of electron holes and poor photocatalytic performance.In recent years,it has become an effective way to improve the photocatalytic performance of BiOX through semiconductor composite and plasma surface modification.The modified treatment of low-temperature plasma can not only inhibit the separation of the electronic cave of the photocatalyst,but also expand its absorption range of visible light.Based on this,in this paper,BiOX,BiOX/ZnO,Bi2WO6 and Bi2WO6/BiOX composite heterojunction photocatalyst materials were successfully synthesized by hydrothermal synthesis,and the surface of the samples was modified by low-temperature plasma.Then its photocatalytic performance was evaluated by methyl orange degradation(MO).Further,we grow different morphologies on the surface of porous nickel carrier Bi@BiOBr/ZnO film,mainly studying the effect of plasma pretreatment on the surface of porous nickel,hydrothermal synthesis time and[Bi/Zn]content Bi@BiOBr/Study on the structure and photocatalytic properties of ZnO film.The experimental conclusions are as follows:(1)The photocatalytic performance of BiOX and BiOX/ZnO composite heterojunction photocatalysis materials prepared by hydrothermal method is significantly higher than that of single BiOX,and the composite samples have enhanced response to visible light,and the band gap decreases.Then the surface was further modified by hydrogen(3%)argon plasma.The study showed that the crystal structure and morphology of the surface were not changed after plasma modification,but its response range to visible light was significantly enhanced,while the band gap value was reduced,and the photocatalytic performance was significantly improved.(2)The foam nickel carrier is pretreated in different plasma atmospheres(O2,H2/Ar,Ar,CF4,CH4),and then grown on its surface by a simple hydrothermal synthesis method Bi@BiOBr/ZnO film.The results show that the same precursor solution and hydrothermal synthesis growth time and temperature are used for pretreatment under different plasma atmospheres Bi@BiOBr/ZnO films have different morphologies.Moreover,due to the strong adsorption capacity and large surface area of O2-B/Z and Ar-B/Z,the absorption intensity of visible light and the degradation rate of methyl orange solution MO are the highest;By changing the hydrothermal synthesis time,it is found that the band gap width of the film sample will change with the hydrothermal synthesis time,and the longer the hydrothermal synthesis time,the smaller the band gap value.Experiments show that when the hydrothermal synthesis time is 6h Bi@BiOBr/The best time to prepare ZnO film;Finally,by changing the content of[Bi/Zn]in the precursor solution of BiOBr/ZnO,it is proved that when the content of KBr is 0.36g,the degradation effect of the composite film is the best,and the best degradation effect is 91%.(3)Based on the hydrothermal synthesis process,Bi2WO6 and Bi2WO6/BiOCl photocatalyst powders were successfully prepared,and the photocatalytic performance of Bi2WO6/BiOCl composite material was improved by about 10%compared to that of a single Bi2WO6.Then,the surface of pure Bi2WO6 and Bi2WO6/BiOCl photocatalyst powders was further modified by hydrogen(3%)argon low-temperature plasma.The results showed that low-temperature plasma can create more reactive sites on the surface of pure Bi2WO6 and Bi2WO6/BiOCl photocatalyst powders,thereby accelerating their catalytic reaction and enhancing their ability to photocatalytic degrade dye wastewater.