Study On Preparation And Application Of Fe³⁺ Doped Tetragonal BiVO₄

In the past few decades,there is a new kind of environmental control technology has caused wide public concern in environmental purification.For the sake of making better use of solar energy,a large number of studies have focused on the visible light range,this can make semiconductor photocatalyst having a efficient response.About the application of photocatalyst,which still exist many issues to be dealed so far,such as the transfer of a small amount of charge,as well as the weak capacity of surface adsorption and so on.Bismuth vanadate(BiVO4)as a promising semiconductor photocatalyst,but remain many issues itself,which limits its photocatalytic activity in a certain range.In order to deal with those issues,a lot of measures were attempted to enhance its photocatalysis ability.Due to tetragonal phase bismuth vanadate(t-BiVO4)of forbidden band width is 2.9 eV,can only happen in the uv range response,almost does not occur within the scope of visible light response,and the ultraviolet light is only a fraction of the sun.Therefore,how to find a way to improve the photocatalytic properties of bismuth vanadate(t-BiVO4)has became the research focus.Passes test,we found that the tetragonal phase bismuth vanadate doped Fe3+,after testing,found that the bismuth vanadate series of iron doped powder preparation,not only can the bismuth vanadate tetragonal structure,but also enhance the photocatalytic activity.In this paper,the Bi(1-x)FexVO4 powders were synthesized by chemical precipitation method,in addition,we would like to further investigate the photocatalytic properties by doping different proportions of Fe3+.1.The Bi(1-x)FexVO4 powders were synthesized by chemical precipitation method,and the purity of the samples under different pH values and the degradation of rhodamine B in the visible range were investigated.Through determination,a large number of experiments we found that under the strong acid condition,the prepared Bi(1-X)FexVO4 series powder,still maintained a bismuth vanadate tetragonal structure,and when the doping amount of Fe3+ is over 60%,the photocatalytic properties of the powders were obviously enhanced little by little,especially the proportion of Bi0.3Fe0.7VO4 powder the photocatalytic performance,the photochemical catalysis was obviously overmached than that of monoclinic bismuth vanadate powder.2.By first principle calculation,the band width,light absorption,after studying doped iron from theory,the change of the energy band of tetragonal bismuth vanadate.After calculation,pure tetragonal phase vanadium bandgap bismuth is 2.875eV,close to the experimental results on 2.9 eV,and after the theoretical arithmetic,we found that the iron doped tetragonal phase bismuth vanadate,the band gap decreases,iron doping in 12.5%,the band gap is 2.6eV,the band gap decreases,which means to enhance light absorption,demonstrated that the iron doped tetragonal phase bismuth vanadate theoretically,the optical absorption increases,as a result that the photocatalytic performance is better,which is in accorandance with the experimental results.3.The chemical precipitation method,preparation of powder series of iron doped monoclinic bismuth vanadate,After experimentation and testing,we found that after the monoclinic bismuth vanadate doped iron,the photocatalytic performance actually decreased gradually,not like tetragonal vanadate,showed an increasing trend,and the tetragonal Bi0.3Fe0.7VO4 the proportion of powder,is still the best degradation efficiency.4.The chemical precipitation method,hydrothermal synthesis and calcination after boiling into bismuth vanadate monoclinic phase,the prepared monoclinic bismuth vanadate,and the powder quality.Under visible light exposure,the same concentration of rhodamine B was degraded,as we can be obtained from the experiment,by three different methods of synthesis of monoclinic bismuth vanadate(m-BiVO4),the photocatalytic effect is the best method of chemical precipitation,next in importance by hydro-thermal synthesis,degradation effect is the worst in high temperature after bismuth vanadate.However,the best degradation effect of monoclinic bismuth vanadate(m-BiVO4),the degree of light is still less than the tetragonal phase Bi0.3Fe0.7VO4 powder.