氮和碳共掺杂TiO2纳米晶的制备及可见光催化性能

以钛酸四丁酯为钛源, 冰醋酸为抑制剂, 超细铵盐为固体载体, 采用新型溶胶-凝胶法制备了氮和碳共掺杂TiO2纳米晶(N-C-TiO2) 光催化剂. 透射电子显微镜(TEM)结果表明, N-C-TiO2样品颗粒均匀, 尺寸细小, 且分散性好; 热失重分析(TGA)、 X射线粉末衍射(XRD)和X射线光电子能谱(XPS)研究结果表明, 复合干凝胶经低温热处理, 使铵盐载体分解、 挥发去除, 样品为单一的锐钛矿相, N和C原子扩散进入晶格结点或间隙位置, 与TiO2化学键结合; 氮气等温吸附-脱附结果表明, 样品比表面积高达356 m2/g, 孔体积为0.27 mL/g. 以氙灯为可见光光源, 罗丹明B水溶液为模拟污染物, P25为参比催化剂, 在辐射强度为100 mW/cm2的可见光照射条件下, N-C-TiO2具有很高的光催化活性, 其可见光催化活性明显高于P25.

Preparation and Visible Light Photocatalytic Properties of Nitrogen and Carbon Co-doped TiO2 Nanocrystalline

Nitrogen and carbon co-doped TiO2 nanocrystalline(N-C-TiO2) photocatalyst was prepared by a new method of sol-gel process using titanium n-butoxide [Ti(OC4H9)4] as raw materials, acetic acid(HAc) as a modifier, and ammonium carbonate(C2H11N3O5) as solid substrates. The samples were characterized by thermogravimetric analysis(TGA), transmission electron microscopy(TEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and N2 adsorption-desorption isotherms analysis. The hydrous TiO2 particles were deposited onto the surface of ultrafine ammonium salt particles during hydrolysis of Ti(OC4H9)4. When the complex dry gel was calcined at lower temperature(300℃), the hydrous TiO2 particles dehydrated and crystallized, and the N and C atoms diffuse into crystal lattice of TiO2.The thermal dissociation of ammonium salt can control the particle size and inhibit the agglomeration of anatase TiO2 in the calcining process and simultaneously enhance phase transformation from amorphous TiO2 to anatase phase. The N-C-TiO2 samples have smaller particle sizes, lower agglomeration and large specific surface area, which exhibit significantly higher photocatalytic activity than the P25 on the degradation of rhodamine B(RB) in water under visible light irradiation.