氟钒锰共掺对TiO2柱撑膨润土光催化脱硝性能的影响

Effect of F,V and Mn co-doping on the catalytic performance of TiO2-pillared bentonite in the photocatalytic denitration

采用溶胶-凝胶法制备氟钒锰共掺改性的TiO2柱撑膨润土,使用XRD、氮吸附、UV-vis光谱和SEM等手段对其进行了表征测试,并对其室温下的可见光催化脱硝性能进行了评价研究。结果表明,对于NO质量浓度为661μg/m^3的气体,F-V-Mn共掺TiO2柱撑膨润土的光催化脱除效率近似达到100%,而NO质量浓度提升至1657μg/m^3时,光催化效率为81.9%,与未柱撑的F-V-Mn共掺TiO2相比提高了33.8%。F-V-Mn共掺TiO2柱撑膨润土上光催化脱反应速率常数最大,是V-Mn共掺TiO2柱撑膨润土的2倍,且前者的抗水和抗SO2中毒能力也更强。TiO2柱撑不仅保留了膨润土的片状晶体结构,而且使膨润土层间距由0.667nm增大至0.710nm,吸附能力增强;同时,掺杂元素能抑制TiO2金红石相生长,降低TiO2禁带宽度,提高可见光响应,延长使用寿命,拓宽应用范围。

F,V and Mn co-doped TiO 2-pillared bentonite was prepared by the sol-gel method and characterized by XRD,nitrogen sorption,UV-vis spectroscopy,SEM,etc.;its performance in the photocatalytic denitration of NO was investigated under visible light irradiation at room temperature.The results indicate that the photocatalytic denitration efficiency of F-V-Mn co-doped TiO 2-pillared bentonite for NO at a concentration of 661μg/m^3 is approximately 100%;when the concentration of NO increases to 1657μg/m^3,the photocatalytic efficiency decreases to 81.9%,which is however 33.8%higher than that over the unpillared F-V-Mn co-doped TiO 2.The reaction rate constant over the F-V-Mn co-doped TiO 2-pillared bentonite is twice as high as that over the V-Mn co-doped TiO 2 pillared bentonite;moreover,the F-V-Mn co-doped TiO 2-pillared bentonite also displays improved resistance against water and SO 2 poisoning.TiO 2 pillars can not only retain the flaky crystal structure of bentonite,but also increase the distance between bentonite layers from 0.667 to 0.710 nm and enhance the adsorption capacity.Meanwhile,the doping elements can inhibit the growth of TiO 2 rutile and reduce the band gap of TiO 2,which is effective in improving the response to visible light,prolonging the service life,and broadening the application range of TiO 2 for the photocatalytic denitration.