Study On Photocatalytic And Piezocatalytic Performance Of Sodium Bismuth Titanate

Possessing a great potentail in dealing with worldwide environment and enengy crisis,semiconductor photocatalyst has drawn tremendous attention.Owing to undiserable energy gap,some traditonal photocatalysts,which have certain flaws,including inactivity to visiable light,serious combination of carriers,can not be commercialized.So development in Visble-light active photocatalysts is necessary.Some piezoelectric semiconductors with built-in electric field,able to accelerate carrigers seperation,have been exploited in photo-piezoelectric synergistic catalysis.Among of them,various layered Bi-based photocatalysts,in case of their piezoelectric ability,have inspired numerious researchers’instrests.Given the feasible manufacture,low cost,satisfactory piezoelectric ability,sodium bismuth titanate（NBT）has been setted as the objects,and the article focused on their photo-and piezoelectric catalysis activity and mechanism.Na_0.5Bi_0.5TiO₃ and Na_0.5Bi_4.5Ti₄O₁₅ are the research objects of this article.Firstly,hydrothermal method is used to prepare Na_0.5Bi_0.5TiO₃ with different morphologyby adjusting the concentrations of NaOH solution.When the concentration is more than10mol/L,regular and well-distributed Na0.5Bi0.5TiO3 cubic nanoparticles were obtained.In order to enhance the light response and photocatalytic activity of Na_0.5Bi_0.5TiO₃,BiOI was in-situ deposited on the surface of Na_0.5Bi_0.5TiO₃ to form BiOI/Na_0.5Bi_0.5TiO₃heterostructure photocatalysts.Through MO photodegradation experiments,all the composite photocatalysts exhibit better photocatalytic activity than that of BiOI and Na_0.5Bi_0.5TiO₃.Among all the samples,Na_0.5Bi_0.5TiO₃（Ti:I（mole ratio）=1:1）has the best performance,which can even effictively photodegrade MO,NPA,Ph,Tatracycline.Finally,band potential of Na_0.5Bi_0.5TiO₃ and BiOI are calculated by Mott-Schottky curves and DRS graphs,and a mechanism of BiOI/Na_0.5Bi_0.5TiO₃ is proposed.By altering the temprature and the mole ratio of raw materials/salt,Na_0.5Bi_4.5Ti₄O₁₅shows different morphology.It can be found from SEM images that Na_0.5Bi_4.5Ti₄O₁₅,when the sinerited temprature is 800 ^oC,is composed of regular square nanosheets.Besides,this sample shows simmilar efficiency in photo-and piezoelectric degradation of Tatracycline,respectively.To further enhance the degradation rate,a variety of metal elements（Fe,V,Sr,etc）are doped in photocatalyst.Correspondingly,sample’s color changes and its light absorption is promoted,meanwhile,the morphology changes from square nanosheets to aggregates of nanoparticles...