不同煅烧温度的N-TiO_2制备、表征及可见光催化性能

Preparation and characterization of N-TiO_2 nanomaterials calcinated at various temperatures and their visible light photocatalytic performance

以钛酸丁酯为钛源,氯化铵为氮源,采用溶胶-凝胶法,不同煅烧温度条件制备N掺杂TiO_2纳米材料,采用X射线粉末衍射(XRD)、傅里叶变换红外(FT-IR)、扫描电镜(SEM)、紫外-可见漫反射(UV-Vis DRS)手段对其进行表征,并通过降解腐殖酸(HA)实验,探讨N-TiO_2可见光催化性能。结果表明,制备的光催化纳米材料为锐钛矿相,TiO_2光响应范围可拓宽到可见光区;煅烧温度是影响可见光催化活性的重要因素,350℃煅烧的N-TiO_2可见光催化活性最佳,光反应140min后,对初始浓度为5 mg/L的HA溶液降解率达80.32%,光催化反应过程符合准一级动力学,煅烧温度过高或过低,动力学反应速率常数呈现不同程度的减小,降解反应速率明显下降。

N-TiO_2 photocatalyst was synthesized using a sol-gel method in the presence of tetrabutyl titanate and ammonium chloride under different calcination temperatures. The prepared samples were characterized by Xray diffraction（ XRD）, Fourier transform infrared spectroscopy（ FT-IR）, scanning electron microscopy（ SEM）,and UV-Vis diffuse reflectance spectroscopy（ DRS）. The photocatalytic degradation of humic acid（ HA） was also examined to study the visible photocatalytic activity. The crystallographic phase of the N-TiO_2 photocatalyst was identified as the anatase phase and its response extended to the visible light region. Furthermore,calcination temperature had a significant effect on the photocatalytic activity of the prepared material,with the ideal annealing temperature for the as-prepared N-TiO_2 materials exhibiting optimal visible photocatalytic activity being 350 ℃. In addition,a degradation rate of ≤80. 32% was obtained after 140 min with an initial HA concentration of 5 mg / L. The photocatalytic degradation process followed pseudo-first-order kinetics,and excessively high or low calcination temperatures caused the degradation rate to decrease gradually.