Study on photocatalytic nitrobenzene reduction to aniline over hierarchical flower-like Cu/TiO2
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摘要: 采用醇解溶剂热法制备金属Cu修饰的系列多级花状TiO2光催化剂（X% Cu/TiO2），并以可见光光催化硝基苯还原制苯胺为模型反应评价其光催化性能. 结果显示：3.3% Cu/TiO2光催化剂展现出优异的催化活性，可见光催化3 h硝基苯的转化率达到83%. 主要原因有两个方面：多级介孔结构增加了催化剂比表面积，促进了硝基苯吸附、扩散及其与催化剂的接触；金属Cu的引入降低了催化剂的带宽，增强了光生电子和空穴的分离能力，进而提升了其光催化性能. 此外，3.3% Cu/TiO2光催化剂表现出良好的稳定性，具有一定的潜在实用价值.Abstract: A series of metal Cu-modified hierarchical flower-like TiO2 catalysts (X% Cu/TiO2) was prepared by using an alcoholysis solvothermal method, and their photocatalytic performance were evaluated by using visible-light photocatalytic reduction of nitrobenzene to aniline as a model reaction. The results show that 3.3% Cu/TiO2 photocatalyst exhibits excellent catalytic activity, achieving 83% nitrobenzene conversion under visible-light irradiation for 3.0 h. There are two main attributions : firstly, the hierarchical structure enlarged the catalyst’s surface area and thus, improved the adsorption and diffusion of nitrobenzene and its contact efficiency with catalyst; secondly, the introduction of metal Cu reduced the catalyst’ energy band and enhanced the separation ability of photoelectron-hole, and thus enhanced the photocatalytic activity. In addition, 3.3% Cu/TiO2 also exhibits good stability and shows good potential in practical applications.
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Key words:
- photocatalysis /
- TiO2 /
- hierarchical structure /
- nitrobenzene reduction /
- metal modification
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图 2 不同催化剂的N2吸脱附等温线和孔径分布曲线
Figure 2. N2 adsorption-desorption isotherms and pore size distribution curves of different catalysts
图 7 不同催化剂的紫外可见漫反射光谱图
Figure 7. Uv-vis diffuse reflection spectra of different catalysts
图 8 不同催化剂的硝基苯光催化还原制苯胺的光催化活性
Figure 8. Photocatalytic activities of different catalysts for nitrobenzene reduction to aniline
图 9 不同催化剂的对位取代基硝基苯光催化还原制苯胺活性图
Figure 9. Photocatalytic activities of different catalysts for reduction nitrobenzene with various p-substituents to anilines
图 10 6次循环后3.3% Cu/TiO2的稳定性测试
Figure 10. Recycling test of 3.3% Cu/TiO2 after six cycles
表 1 不同催化剂的物理结构参数
Table 1. Physical parameters of different catalysts
催化剂 比表面积/
(m2·g−1)孔容/
(cm3·g−1)孔径/
nm晶粒尺寸/
nmTiO2 22 0.09 16 22 0.5% Cu/TiO2 28 0.10 14 22 2% Cu/TO2 28 0.11 15 21 3.3% Cu/TiO2 47 0.26 21 21 4.1% Cu/TiO2 39 0.24 23 21 5% Cu/TiO2 39 0.23 23 21 
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