TiO_(2)掺杂改性对UiO-66结构和催化性能的影响

Effect of TiO_(2) doping modification on structure and catalytic performance of UiO-66

为获得具有可见光响应的高活性光催化剂,利用二氧化钛(TiO_(2))对UiO-66掺杂改性,通过水热法合成TiO_(2)@UiO-66.采用扫描电子显微镜(scanning electron microscope,SEM)、X射线衍射(X-ray diffraction,XRD)、傅里叶红外光谱分析(Fourier transform infrared spectroscopy,FTIR)和N_(2)吸附-脱附(N2 adsorption-desorption)等手段,考察TiO_(2)掺杂对UiO-66结构和表面形貌的影响.结果表明,所制备样品均为正八面体结构;改性前UiO-66比表面积高达1270 m2/g,少量TiO_(2)掺杂时,TiO_(2)@UiO-66的比表面积与UiO-66相差无几;TiO_(2)掺杂量增加至15 mmol时,TiO_(2)@UiO-66的比表面积骤减到413 m2/g,TiO_(2)掺杂过多会降低UiO-66的比表面积.以可见光下样品对头孢曲松钠的去除为探针反应考察其催化活性,结果显示,TiO_(2)掺杂量为10 mmol时,可见光照射120 min,TiO_(2)@UiO-66对头孢曲松钠的去除率达到64.86%,是UiO-66的1.28倍.因此,适量掺杂TiO_(2)可以提高UiO-66对头孢曲松钠的去除率.研究可为改性UiO-66光催化剂设计和头孢抗生素污染物的光催化降解提供参考.

In order to obtain a highly active photocatalyst with visible light response,UiO-66 was modified by doping TiO_(2)and TiO_(2)@UiO-66 was synthesized with the hydrothermal method.Scanning electron microscope(SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and N_(2)adsorption-desorption were used to investigate the effect of TiO_(2)doping on the structure and surface morphology of UiO-66.The results showed that all the samples had regular octahedral structure.The specific surface area of UiO-66 was high up to 1270 m^(2)/g before modification,and the specific surface area of TiO_(2)@UiO-66 was similar to that of UiO-66 with a small amount of TiO_(2)doping.When the doping amount was increased to 15 mmol,the specific surface area of TiO_(2)@UiO-66 was decreased sharply to 413 m^(2)/g,since excessive TiO_(2)doping reduced the specific surface area of UiO-66.Removal of ceftriaxone sodium by samples under visible light was used as probe reaction to investigate its catalytic activity.The photocatalytic results showed that the removal rate of ceftriaxone sodium by TiO_(2)@UiO-66 reached 64.86%,which was 1.28 times that of UiO-66,when TiO_(2)doping amount was 10 mmol and visible light irradiation was 120 min.Therefore,appropriate TiO_(2)doping can improve the removal rate of UiO-66 to ceftriaxone sodium.This work may provide new insights into the design of modified UiO-66 photocatalyst and the photocatalytic degradation of cephalosporins.