N、F共掺杂TiO_2可见光响应光催化剂的酸催化水解法制备及表征

Characterization of Visible Light Response N-F Codoped TiO_2 Photocatalyst Prepared by Acid Catalyzed Hydrolysis

采用酸催化水解法由TiCl4、NH4F混合液合成N、F共掺杂可见光响应TiO2光催化剂(TONF).以苯酚为模型物,考察了催化剂在可见光区、紫外光区的催化活性.采用X射线光电子能谱(XPS)、紫外-可见漫反射光谱(DRS)、X射线衍射(XRD)、扫描电子显微镜(SEM)及低温氮物理吸附对光催化剂的晶相结构、光谱特征和表面结构等进行表征.结果表明,适量的N、F共掺杂TONF催化剂表现出较高的可见光催化活性.N、F共掺杂可显著提高TiO2分散性能,促进锐钛矿相的形成,抑制其向金红石相转变,提高相转变温度.N掺杂可提高TiO2在可见光区的吸收;F掺杂可使TiO2能隙变窄.

N-F codoped TiO2 （TONF） photocatalysts were prepared using acid catalyzed hydrolysis method from mixed aqueous solution of TICl4 and NH4F. The photocatalytic activity of the TONF was evaluated through the degradation of phenol under both visible and UV light irradiation. X-ray photoelectron spectroscopy （XPS）, UV-Vis diffuse reflectance spectroscopy （DRS）, X-ray diffraction （XRD）, scanning electron microscope （SEM）, and N2 adsorption isotherm were used to characterize the obtained powders. The results showed that N-F co-doped TiO2 exhibited significant improvement of visible light catalytic activity. N-F co-doping could improve dispersion of TiO2, inhibit particle size agglomeration, and retard phase transformation. Doped N could extend the light response of TiO2 to visible light region. In addition, narrower band gap formed by F-doping was beneficial to the high visible light photocatalytic activity.