水杨酸分子印迹掺氮TiO_2粉末的制备及在可见光下的选择性光催化研究

【目的】改善TiO_2在可见光下对污染物的选择性降解能力。【方法】采用改进的分子印迹溶胶-凝胶技术,以尿素、水杨酸分别为氮源和模板分子,制备水杨酸分子印迹掺氮TiO_2粉末。通过X射线衍射(XRD)、透射电镜(TEM)、紫外-可见光漫反射吸收光谱(UV-Vis DRS)和低温N_2物理吸附-脱附(BET)等技术对制备样品进行表征。【结果】样品均为锐钛矿相,氮掺杂致使TiO_2光吸收带边红移,分子印迹使TiO_2具有了更为发达的孔结构和孔型,掺杂和分子印迹均有效地增大了比表面积。可见光下,与催化降解苯甲酸及甲基橙相比,分子印迹掺氮TiO_2对水杨酸的选择性降解率较高,达96.0%。【结论】水杨酸分子印迹和氮掺杂有效地改善了TiO_2的选择性和可见光活性。

Preparation of salicylic acid molecularly imprinted and N-doped TiO2 powders and their selective photocatalytic activity under visible light

Objective]To improve selective degradation ability of catalyst ( TiO2 ) under visible light.Method]Salicylic acid molecularly imprinted and N-doped TiO2 powders were synthesized by an im-proved molecularly imprinted sol-gel technique using urea as a nitrogen ( N) source and salicylic acid as a template molecule. The samples were characterized by XRD, TEM, UV-Vis diffuse reflectance spectro-photometer and N2 adsorption-desorption.Result]All samples were anatase. The red-shift of absorption band was caused by doping nitrogen to TiO2. The better-developed pore structure and pass were due to molecular imprinting technique, and the enlarged specific surface area was generated by N-doping and molecularly imprinting. Compared to benzoic acid and methyl orange, TiO2 selective photodegradation rate of salicylic acid (96. 0%) was higher under visible light using molecularly imprinting and N-doping.Conclusion]The selectivity and visible-light photoactivity of TiO2 can be effectively improved using sali-cylic acid molecularly imprinting and N-doping.