BiVO_4纳米片的水热合成及可见光催化性能

Hydrothermal synthesis and photocatalytic property of BiVO_4 nanosheets

以Bi(NO3)3.5H2O和NH4VO3为原料,EDTA为络合剂,辅助水热法合成BiVO4方形纳米片;采用X射线衍射(XRD)、扫描电镜(SEM)、高分辨透射电镜(HRTEM)、拉曼光谱(Raman)、紫外-可见漫反射光谱(DRS)、比表面分析(BET)等测试手段对产品进行表征和分析;探讨pH值对BiVO4颗粒物相与形貌的影响。结果表明:EDTA辅助水热法能够合成结晶良好单斜白钨矿BiVO4方形纳米片,该BiVO4方形纳米片宽度约为0.6～1.0μm,厚度约为200～300 nm;相比m-BiVO4颗粒,该片状样品的紫外-可见光吸收边稍微发生红移,其能带隙减小至2.37 eV;变化溶液pH值可制备出片状、方片状、方块状和砖块状BiVO4颗粒。这些BiVO4颗粒在可见光范围内都具有一定的光催化活性,其中BiVO4方形纳米片对亚甲基蓝具有最强的可见光催化降解活性,可见光照射120 min后浓度为10mg.L-1亚甲基蓝溶液的降解率可达到100%。

Using Bi（NO3）3-5H2O and NH4VO3 as raw materials,square BiVO4 nanosheet were synthesized by hydrothermal method with ethylenediamine tetraacetic acid（EDTA） as chelating agent.The properties of the as-prepared samples were investigated by XRD,SEM,HRTEM,Raman,DRS and BET tests.The effect of pH on the phase and morphology of samples was studies.The results show that high crystallinity BiVO4 nanosheet shapes with crystalline monoclinic structure,whose width varies in the range of 0.6-1.0 μm and length in the range of 200-300 nm,can be obtained via a hydrothermal route assisted by EDTA.Compared with m-BiVO4 particle,the absorption band of the microrod assisted by 2.0 g EDTA presents a little red shift and its band gap is narrowed to 2.37 eV.The BiVO4 samples with platelike,square shape,square massive,brick-shaped structure can be obtained by controlling the pH value in the synthesis process.These BiVO4 samples have certain photocatalytic activity under the visible light irradiation.A much higher photocatalytic activity of the square nanosheet is found under visible light irradiation with a 100% degradation of methylene blue（MB） of 10 mg-L-1 solution after visible light irradiation for 120 min.