掺杂可见光催化剂Bi_2WO_6的制备及降解效果研究

Preparation and degradation of doped visible light catalyst Bi_2WO_6

本文采用水热法在不同的条件下(不同温度、不同pH值、不同浓度的表面活性剂)制备了可见光催化剂Bi_2WO_6,同时也掺杂了Fe制备了Bi_2WO_6,并改变了原材料的配比,制备了Bi_2O_3-Bi_2WO_6。实验结果表明:Bi2WO_6的禁带宽度在2.83eV,有良好的可见光催化性能。Bi_2O_3-Bi_2WO_6拓宽了禁带宽度,使得禁带宽度为3.05eV。催化剂的光催化活性和催化剂的晶型、颗粒的半径大小、比表面积的大小都密切相关。然而催化剂的形貌、粒径、比表面积又与制备条件密切相关,只有在特定形貌下,粒径小并且均匀的情况下的催化剂的催化活性才好。在酸性条件下由于抑制了硝酸铋的水解,从而制备的催化剂的催化活性优于在碱性条件下制备的催化剂。催化剂在降解罗丹明B的实验中,催化时的去乙基作用使得罗丹明B溶液的主峰发生蓝移,主峰由553nm移动到了495nm。催化剂的去乙基作用于只有在可见光的照射下才会发生,并且去乙基作用使得光催化降解反应的初速度加快。催化剂的吸附性能影响去乙基反应,吸附性能差的催化剂发生去乙基反应的速度也低。催化剂在降解染料时对染料有选择性,本实验所制备的催化剂对罗丹明B的降解效果高于对甲基橙的降解效果。

In this paper, the visible light catalyst Bi2WO6 was prepared by hydrothermal method under different conditions (different temperature, different pH value, different concentration of surfactant), and Bi2 WO6 was also prepared by doping Fe, and the ratio of raw materials was changed. Bi2O3 - Bi2WO6 . The experimental results show that the band gap of Bi2 WO6 is 2. 83eV, which has good visible light catalytic performance. Bi2 O3 - Bi2 WO6 broadens the forbidden band width to a band gap of 3. 05 eV. The photocatalytic activity of the catalyst is closely related to the crystal form of the catalyst, the radius of the particles, and the specific surface area. However, the morphology, particle size and specific surface area of the catalyst are closely related to the preparation conditions. Only in the specific morphology, the catalytic activity of the catalyst is small and uniform. The catalytic activity of the prepared catalyst is superior to that of the catalyst prepared under alkaline conditions due to inhibition of hydrolysis of cerium nitrate under acidic conditions. In the experiment of degrading rhodamine B,the deethylation of the catalyst caused the blue peak of the main peak of Rhodamine B solution?and the main peak moved from 553nm to 495nm. The deethylation of the catalyst occurs only under the illumination of visible light,and the deethylation action accelerates the initial rate of the photocatalytic degradation reaction. The adsorption performance of the catalyst affects the deethylation reaction,and the rate of the deethylation reaction of the catalyst having poor adsorption performance is also low. The catalyst is selective to dyes when degrading dyes. The degradation of rhodamine B by the catalyst prepared in this experiment is higher than that of methyl orange.