溶胶凝胶法制备氮掺杂二氧化钛及其可见光活性的研究

室温下采用溶胶凝胶法,以氨水为氮源制备出淡黄色氮掺杂二氧化钛粉末。以TG-DSC、XRD、UV-Vis漫反射吸收光谱以及XPS等手段对二氧化钛进行了表征。结果显示,所制备氮掺杂二氧化钛均为锐钛矿相,且掺杂引起光催化剂在可见光区的光吸收。以甲基橙水溶液在紫外及可见光下的脱色率为光催化活性评价依据,结果显示纯二氧化钛无可见光活性,而氮掺杂二氧化钛360 min的最大脱色率可达65.3%,说明氮掺杂有效改变了二氧化钛的可见光活性,但其紫外活性逊于纯二氧化钛。另外,在实验范围内所做的N/Ti配比与光活性的关系研究中发现,可见光活性随N/Ti配比的增大有一最佳值,而紫外光活性顺序与可见光活性不同。

STUDY ON PREPARATION OF NITROGEN-DOPED TITANIA BY SOL-GEL TECHNIQUE AND ITS VISIBLE LIGHT ACTIVITY

Yellowish nitrogen-doped titania with nitrogen source from ammonia was prepared by sol-gel method in room temperature.The titania catalysts were characterized with TG-DSC,XRD,UV-Vis diffuse reflectance spectrophotometer and XPS.The result showed that all titania were anatase,and the doping of nitrogen could extend the absorption shoulder into the visible light region.Their photoactivities were estimated in the system of orange methyl aqueous solution under the irradiation of UV and visible light,respectively.The nitrogen-doped titania showed higher visible-light activity for the best decoloration of methyl orange reached up to 65.3% in 360min under visible light,while the pure ones showed no visible light activity.The results indicated that doping of nitrogen improved the visible-light activity of titania,but the UV activity of nitrogen-doped titania was worse than that of the pure ones.In addition,there was an optimum value with the increase of N/Ti proportioning corresponding to the best visible-light activity,but different order for UV activity.