前驱溶液的碱浓度对BiVO4粉体的微波水热法制备及光催化性能的影响

摘要

Under different alkali concentrations of the precursor solution BiVO4 powers were synthesized by microwave-hydrothermal method at 200℃, using Bi（NO3）3·5H2O and N H4VO3 powders as raw materials. The phases, structures and morphologies of BiVO4 photoeatalysts were characterized respectively by XRD, FESEM, BET, and UV-Vis methods. The photocatalytic properties of the BiVO4 powders prepared under the dif-ferent alkali concentrations were also studied. The powder prepared under the precursor dissolved deionized wa- ter was BiVO4 mixed crystal with monoclinic phases and tetragonal phases with 1-3μm octahedral structure. When the precursor was dissolved into HNOa and NaOH solutions, the as-prepared powder was 3μm pure monoclinic ball-like BiVO4. When the concentration of NaOH was increased to 4mol/L, the powder became the mixed crystal with 2μm fishbone-like BiVO4. The results of photocatalytic activity show that the order of the photocatalytic activities under UV-light was BiVO4 （deionized water）〉BiVO4 （4mol/L NaOH）〉BiVO4 （2mol/L NaOH）. Under the visible-light irradiation, the order was BiVO4（4mol/L NaOH） 〉 BiVO4 （deionized water） 〉BiVO4 （2mol/L NaOH）.%以Bi（NO3）3·5H2O和NH4VO3为原料，采用微波水热法在200℃不同前驱液碱浓度下制备了BiVO4粉体。利用XRD、FE-SEM、BET、UV-Vis等手段研究了前驱液碱浓度对BiVO4晶型、结构及形貌的影响，并对不同前驱液碱浓度下合成粉体的光催化性能进行了研究。溶于纯水获得的粉体是单斜相和四方相1-3μm八面体结构的BiVo。混晶。溶于HNO。和NaOH溶液时制得粉体为纯单斜相3μm大小球状BiVO4，NaOH增加到4mol／L时为2tam大小鱼排骨状BiVO4的混晶。光催化结果表明，紫外光下光催化活性顺序为：BiVO4（纯水）〉BiV04（4mol／LNaOH）〉BiVO4（2mol／LNaOH），可见光下光催化活性顺序为：BiVO4（4mol／LNaOH）〉BiVO4（纯水）〉BiVO4（2tool／LNaOH）。