异质结光催化剂BiVO_4/RGO的合成及其光催化降解罗丹明B的研究

Photocatalytic Degradation of RhB over BiVO_4/ Reduced Graphene-oxide Heterojunction Composite Photocatalyst under Light Irradiation

采用溶胶-凝胶法制备具有异质结构光催化剂BiVO_4/RGO,通过XRD、SEM、TEM、FT-IR、XPS等对催化剂进行表征分析,并以罗丹明B为目标污染物,考察了BiVO_4/RGO的光催化活性。XRD结果表明,合成的复合催化剂均为单斜相晶体结构,RGO的引入没有改变Bi VO4的物相,SEM、TEM图像证明,两者充分接触形成复合结构,RGO良好的导电性增加了催化剂表面的活性位点,有效促进光生电子的迁移,抑制电子-空穴对的再复合,FT-IR、XPS分析说明RGO和BiVO_4存在复合体系中,且都保持各自原有化合态,综合分析两者成功形成异质结复合结构,相比单体BiVO_4,复合物明显拓宽光吸收范围。当RGO的含量为6wt%时,实验条件下罗丹明B的降解率达90.19%,催化性能最佳,五次循环实验后,6wt%Bi VO4/RGO的降解率仍能保持在85%左右。

BiVO_4/ RGO composite photocatalyst was synthesized by sol-gel method,the as-prepared samples were characterized by X-ray diffraction( XRD), Scanning electron microscopy( SEM),Transmission electron microscope( TEM), Fourier transform infrared spectroscopy( FT-IR), X-ray photoelectron spectroscopy( XPS),using Rh B as the model pollutant,the photocatalytic activity of BiVO_4/ RGO was evaluated. The results indicate that the heterojunction structure composite photocatalysts were monoclinic crystal structure,the phase of BiVO_4 was not changed after introduction of RGO,BiVO_4 nanoflakes were distributed on the surface of RGO,BiVO_4 and RGO existed in the composite system,the heterostructure formed because of the good conductivity and large surface area of RGO,the active sites of the composites increases and it plays a crucial role that the heterostructure in electronic-hole recombination,the photocatalytic performance of BiVO_4/ RGO enhance,BiVO_4/ RGO has more strong light response. 6wt% BiVO_4/ RGO exhibite the highest photocatalytic degradation efficiency and stability.