Preparation And Photocatalytic Performance Of Bismuth Molybdate And Its Composites

The wide application of semiconductor photocatalysis technology in solving energy and environment problems nowadays makes it a hot research area today.Among numerous semiconductor photocatalytic materials,Bi₂MoO₆,as a member of the Aurvillius family,can respond to visible light due to its band gap of about 2.6ev.So,it has attracted researchers'attention.However,as the photo-generated electron hole pairs of pure phase Bi₂MoO₆are prone to compound and Bi₂MoO₆has low quantum efficiency,its photocatalytic performance is thus restricted.It is known to all that the photocatalytic performance of semiconductor photocatalytic materials can be improved by morphology control,ion doping,and compound with other materials.In this paper,the photocatalytic performance of Bi₂MoO₆,was enhanced by morphology control,i.e.preparing flower-like Bi₂MoO₆by solvothermal method,and compound with ZIF-8,Bi OCl and Bi₁₂O₁₅Cl₆.The experimental procedures are as follows:A series of Bi₂MoO₆/ZIF-8 photocatalysts were prepared by solvothermal method and self-assembly method.Their phase composition,micro-morphology and optical property were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),X-ray photoelectron spectroscopy(XPS),Fourier Transform Infrared Spectrometer(FTIR),photoluminescence(PL),etc.Then they were used to degrade Methylene Blue(MB),a simulated pollutant prepared in advance,to evaluate their photocatalytic performance.By observing the degradation degree,it can be concluded that the compound Bi₂MoO₆/ZIF-8-3photocatalyst has better photocatalytic performance than the single-composite Bi₂MoO₆or ZIF-8.This is because the load of ZIF-8 on the flower-like Bi₂MoO₆can effectively promote the separation of its photo-generated electron hole pairs,thus limiting the compound of hole pairs and improving its photocatalytic performance.BiOCl/Bi₂MoO₆composite was synthesized by solvothermal method,and its micro-morphology,phase structure and photocatalytic activity were studied.The results showed that the Bi₂MoO₆nanosheets distributed uniformly on the square-shaped Bi OCl,and the composite's photocatalytic performance were influenced by the amount of Bi OCl.By degrading MB under visible light,it was found that when the mass fraction of Bi OCl in the composite was 9wt%,Bi OCl/Bi₂MoO₆composite exhibited the best photocatalytic activity,and the degradation efficiency was increased by 59%and 31%respectively compared with the pure phase Bi OCl and Bi₂MoO₆.In addition,the BMC-9 catalyst still had high photocatalytic activity after repeated use.The Bi₁₂O₁₅Cl₆/Bi₂MoO₆catalyst was prepared by solvothermal method and calcination method,and the effect of Bi₁₂O₁₅Cl₆amount added was systematically researched on the micro-morphology and photocatalytic performance of Bi₂MoO_6.The composite's photocatalytic performance was measured by degrading rhodamine B(Rh B)under visible light.The results showed that when the molar ratio of Bi₁₂O₁₅Cl₆to Bi₂MoO₆in the composite was 2 to 5,the composite had the best photocatalytic performance,and Rh B was 100%degraded after degraded for 40 minute under visible light.This was because the Bi₁₂O₁₅Cl₆/Bi₂MoO₆catalyst had a larger specific surface area on the one hand,and the energy level match of Bi₂MoO₆and Bi₁₂O₁₅Cl₆facilitated the separation of photo-generated electron hole pairs on the other hand,thus the photocatalytic performance was improved.