Ce掺杂的CNTs-TiO2光催化剂制备及其NO氧化性能

Preparation of Ce doped CNTs-TiO photocatalyst and its NO oxidation performance

为探讨湿法脱硫后光催化在烟气脱硝方面的应用潜力,采用溶胶-凝胶法制备了金属、非金属掺杂的CNTs-TiO2复合光催化剂,并在模拟烟气条件下对所得催化剂的NO氧化性能进行了测试与对比筛选,通过SEM、BET、XRD、Raman、XPS、DRS等手段进行表征。结果表明:TiO2的氧化效率最低,掺杂金属比掺杂非金属的光催化剂的氧化效率略高,复合CNTs的光催化剂的氧化效率明显提高;CNTs-Ce/TiO2比表面积较大,Ti—O键长最短,从而有利于光生电子沿Ti—O键向CNTs转移,可形成更多的三价铈氧化物,有利于催化剂表面的氧吸附;带隙宽度较低以及极大的紫外光吸光度,在NO氧化性能测试中表现出最优异的脱除效率,与TiO2相比,效率提升了19%,与CNTs-TiO2相比,效率提升了13%。进一步分析可知:Ce和CNTs具有协同作用,Ce掺杂TiO2可以有效抑制光生载流子的结合,从而提高光催化活性;复合CNTs提高了催化剂比表面积并促进了氧空位的形成,从而促进整个催化氧化反应。

In order to investigate the application potential of photocatalysis on flue gas denitration after wet desulfurization,metal and non-metal doped CNTs-TiO2 composite photocatalyst was prepared by sol-gel method,and the NO oxidation performance of the catalyst was tested and compared under simulated flue gas conditions.SEM,BET,XRD,Raman,XPS,DRS and other means were used to characterize the photocatalyst.The results showed that the oxidation efficiency of TiO2 was the lowest,the oxidation efficiency of photocatalyst doped with metal was slightly higher than that of photocatalyst doped with non-metal,and the oxidation efficiency of photocatalyst compounded with CNTs was significantly improved.Among above catalytic materials,CNTs-Ce/TiO2 had the larger specific surface area and the shortest Ti—O bond length,which facilitated the transfer of photo-generated electrons to CNTs along Ti—O bonds,formed more trivalent cerium oxides,and was conducive to the oxygen adsorption on the catalyst surface.Lower band gap width and great ultraviolet light absorbance showed the most excellent removal efficiency in NO oxidation performance test,and the efficiency increased by 19%compared with TiO2 and by 13%compared with CNTs-TiO2.According to the analysis,Ce and CNTs showed a synergistic effect.Ce doped TiO2 could effectively inhibit the combination of photogenic carriers,thus improving photocatalytic activity.Composite CNTs elevated the specific surface area of the catalyst and the formation of oxygen vacancies,thus promoting the whole catalytic oxidation reaction.