Preparation Of Modified Bismuth Molybdate Photocatalyst And Their Photocatalytic Activities

The water pollution caused by the dye industry has become the focus of humans.Therefore,it is urgent to develop an environmental-friendly scavenger to alleviate and improve the problem in the field of water purification.Hydrotalcite compound is a kind of structurally anionic layered structural material,and the main lamellar structure is an octahedral unit of Brucite.The order characteristics,dispersibility and change ability of the metal elements of the laminate,and the variability of the interlayer anions make it widely used in many fields such as catalytic materials,adsorbent materials,photoelectric conversion materials,environmentally friendly functional materials and so on.The common hydrotalcite structure is a binary composite metal hydroxide system,and more complex hydrotalcites with ternary and quaternary metal element systems.The Bi element compound has a narrow band gap makes the forbidden band width of many compounds less than 3.2 e V,such as Bi2 Mo O6,Bi2WO6,Bi2VO4,Bi2O3,Bi OCl and so on.In order to solve the problem of organic pollutant wastewater,Hydrotalcite and Bismuth molybdate were studied as our research targets.The modified method was used to prepare a more efficient and stable visible light photocatalytic material,which was degraded by visible light under photocatalysis.The organic pollutant wastewater makes its recyclable.The main research contents of this paper manly include three aspects:(1)The Cerium oxide/Bismuth molybdate composite photocatalyst was prepared by hydrothermal method,and then to investigate the effect of Rare earth element doping on the photocatalytic performance of Bismuth molybdate.It can be seen that the enhancement of the photocatalytic performance of Ce O2/Bi2 Mo O6 is attributed to the oxygen storage of Ce O2.In addition,during the preparation process,we also explored the effect of the p H value of the reaction system on the morphology,structure and properties of the synthesized samples..In the alkaline reaction system,the undoped Ce O2 forms Bi3.64Mo0.36O6.55/Bi2 Mo O6 composite,and the doped Ce O2 in the reaction generates Bi3.64Mo0.36O6.55.。(2)The Bi2 Mo O6/Ni Al-LDH composite heterojunction photocatalytic material was synthesized by two-steps hydrothermal synthesis.The semiconductor composite material has higher photocatalytic activity than any single component in the composite under visible light.The photocatalytic activity is enhanced by broadening the light absorption range of the Bi2 Mo O6 photocatalyst in the visible light region,and also adjusting the forbidden band structure of Bi2 Mo O6,and accelerateing the charge transfer on the interface,effectively reducing the recombination rate of photogenerated electrons and holes.The optimum mole ratio of Ni Al-LDH to Bi2 Mo O6 is 10 %.The Rh B solution can be degraded by more than 90 % in 60 min.After photocatalytic activity cycle stability test,the catalytic performance is almost unchanged.(3)The Zn Cu Al-LDHs/Bi2 Mo O6 supported semiconductor photo-catalyst was synthesized by co-precipitation method at room temperature.The photocatalytic performance of the synthesized samples was evaluated by the degradation rate of Rhodamine B under visible light.The photocatalytic activity of Zn Cu Al-LDHs/Bi2 Mo O6-1:1 was increased by three times compared to the original Bismuth molybdate.The increase of photocatalytic degradation rate is attributed to the high dispersion of Bi2 Mo O6,which make the Bi2 Mo O6 nanosheets to expose more active sites.While the electron-hole pairs were effectively separated reduceing the recombination rate of electron-hole pairs.The specific surface area and pore volume of the Zn Cu Al-LDHs/Bi2 Mo O6 increased,which increased effective contact area between catalyst and contaminants to further enhance photocatalytic activity.