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采用溶胶-凝胶法将多壁碳纳米管(MWCNT)和BiVO_4有效复合,制备出一系列不同掺杂量的异质结构复合光催化剂MWCNT/BiVO_4,通过X射线衍射(XRD)、扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)等对催化剂进行表征分析,以罗丹明B为目标污染物,考察了光催化活性和稳定性。结果表明,合成的复合光催化剂均为单斜相晶体结构,MWCNT的引入没有改变BiVO_4的主体物相,两者充分接触、结合形成了复合结构;MWCNT较强的电子俘获能力和大的比表面积增加了复合材料表面的活性位点,MWCNT,BiVO_4存在于MWCNT-BiVO_4复合体系中且都保持各自化合态;综合分析,MWCNT/BiVO_4形成的复合结构为异质结构,异质结构具有典型的提高量子效率的特点,能够有效抑制电子-空穴再复合现象的发生。当MWCNT的含量为2%(质量分数)时,催化剂的效果最好,实验条件下光降解罗丹明B的去除率高达84.08%,五次重复性实验之后,MWCNT/BiVO_4的降解率仍在80%左右。
A series of MWCNT / BiVO 4 heterostructures photocatalysts were prepared by the sol-gel method and the MWCNTs and BiVO 4 were effectively compounded. The structure of MWCNT / BiVO 4 was characterized by X-ray diffraction (XRD), scanning electron microscopy SEM, FT-IR and XPS were used to characterize the catalysts. Rhodamine B was used as the target pollutant and the photocatalytic activity and stability were investigated. The results show that the synthesized composite photocatalyst is monoclinic phase crystal structure. The introduction of MWCNT does not change the bulk phase of BiVO 4, and the two are in full contact with each other to form a composite structure. The strong electron trapping ability and large specific surface area MWCNT and BiVO_4 are present in the MWCNT-BiVO_4 composite system and maintain their respective chemical states; the composite structure of MWCNT / BiVO_4 is heterogeneous and the heterogeneous structure has a typical increase Quantum efficiency characteristics, can effectively inhibit the electron - hole recombination phenomenon. When the content of MWCNT is 2% (mass fraction), the catalyst has the best effect. The removal rate of photodegradation rhodamine B is as high as 84.08% under the experimental conditions. The degradation rate of MWCNT / BiVO_4 is still 80% after five repetitive experiments %about.