Preparation Of Bismuth Tungstate Catalyst And Study On Visible Light Photocatalytic Activity

At present,People aim at finding a tpye of photocatalyst with low cost,simple synthesis method and no subsequent pollution.Bismuth series photocatalysts can be reflected under the visible light due to its unique band structure.Bismuth tungstate(Bi2WO6)is one of the simplest compounds in the bismuth series catalyst materials due to its environmental pollution treatment,organic synthesis,energy utilization,etc.The field has important applications and has the scientific significance of research and development.However,Bi2WO6 is limited by the large band gap and high photoelectron-hole recombination rate.For this reason,a series of visible light catalysts have been prepared by metal ion doping modification of Bi2WO6.A sample material was prepared to treat Rhodamine B(RhB)solution to investigate whether the prepared photocatalyst improved photocatalytic performance.The specific research contents are as follows:(1)At room temperature,the sample material preparation method was simple and safe hydrothermal synthesis technolog.The pure Bi2WO6 sample was successfully prepared,and three metal ions of Ag,Co and La were doped into Bi2WO6 according to different molar ratios.A series of Ag/Bi2WO6,Co/Bi2WO6,La/Bi2WO6 photocatalyst samples were prepared by the same synthesis method.(2)Photocatalytic activity of Bi2WO6 doped with Ag,Co,La metal ions in Rhodamine B solution under ultraviolet and visible light conditions.The ultraviolet light is simulated by a mercury light source,and the visible light is simulated by a xenon light source plus a filter.The results showed that each sample reached a good photocatalytic activity after 120 min of UV irradiation,the removal rate of RhB was higher than 90%,and the photocatalytic activity showed ideal results..Among them,1%Ag/Bi2WO6,1%Co/Bi2WO6,and 3%La/Bi2WO6 exhibited high photocatalytic activity in each metal ion doped series sample.The photocatalytic activity of 3%La/Bi2WO6 was the best,and the removal rate of RhB solution was 98.5%.The 3%La/Bi2WO6 sample still showed the best photocatalytic activity under visible light irradiation.(3)3%La/Bi2WO6 sample with optimal photocatalytic activity was as research target to study the effects of the amount of photocatalyst,the initial concentration of RhB solution and the initial pH of RhB solution on photocatalytic degradation.The results showed that when the catalyst dosage was 0.13 mg,the initial concentration of RhB solution was 4 mg/L,and the pH value was 4.0,the degradation effect was the best,indicating that the degradation of RhB during the reaction was affected by many factors.(4)The samples prepared by the Institute with good photocatalytic activity were characterized by FTIR,BET,DRS,etc.The analysis shows that the basic structure of the photocatalyst sample after doping the metal element is not destroyed.And the doped metal ions do not enter the skeleton of Bi2WO6 to form a bond group.All samples were tabular grain materials and 3%La/Bi2WO6 had the largest specific surface area.Compared with pure Bi2WO6,the metal ion modified sample has narrower band gap,broadens the photoresponse range and improves photocatalytic activity.Furthermore,the active groups which play a leading role in the photocatalytic degradation of the sample under visible light irradiation are discussed,and the possible mechanism of the sample degradation of pollutants is explored.