新型N-TiO2的固相法制备及其光催化性能

以纳米管钛酸为前驱体,以NH4HCO3为N源,先机械研磨使二者混合均匀,再在Ar保护下,于不同温度焙烧4h制得N掺杂TiO2 (N-TiO2),并采用X射线粉末衍射、X射线光电子能谱、紫外-可见吸收光谱、透射电镜及N2吸附-脱附对样品进行了表征.结果显示,N以间隙掺杂方式进入TiO2晶格内.在热处理过程中,生成中间体(...

Preparation of Novel N-TiO2 by a Solid-State Method and Its Photocatalytic Activity

N-doped TiO2 photocatalyst samples were prepared by manual grinding the mixture of nanotube titanic acid and ammonium bi-carbonate followed by annealing the mixture at different temperatures in Ar atmosphere for 4 h.The samples were characterized by X-ray powder diffraction,X-ray photoelectron spectroscopy(XPS),UV-Vis spectrophotometry,transmission electron microscope,and N2 adsorp-tion-desorption.The XPS results indicated that the N was in the form of interstitial atom,i.e.,Ti-O-N bond.The intermediate(NH4)2Ti2O4(OH)2 was formed when the mixture was calcined at different temperatures.Subsequently,the N was released due to the de-composition of(NH4)2Ti2O4(OH)2,resulting in the formation of interstitial-N and oxygen vacancies.N-TiO2 samples showed enhanced visi-ble light absorption and visible light photocatalytic activity because of the existence of interstitial N-dopants and oxygen vacancies.The doped N atoms restrained the phase transition from anatase to rutile at higher temperature.Photocatalytic activity was evaluated by degrada-tion of methyl orange in aqueous solution under xenon lamp irradiation,and the N-TiO2 sample with n(N)/n(Ti)= 4 annealed at 500 °C ex-hibited the highest photocatalytic activity.After 130 min irradiation,the photocatalytic degradation rate of methyl orange was up to 100%,almost 30% higher than that of un-doped TiO2.