中文摘要：

采用柠檬酸酸催化溶胶-凝胶法合成了N掺杂介孔TiO_2,并用XRD、HRTEM、XPS、BET、UV-vis等手段表征了N-TiO_2。测试结果表明,煅烧前的样品是无定形TiO_2,低温煅烧后的产物是锐钛矿TiO_2,而750℃煅烧产物是金红石型。少量N元素的掺杂致使TiO_2的吸收带边位置发生少许红移,移向可见光区域。N_2吸附-脱附和光解甲基橙结果显示,N掺杂介孔TiO_2（3.0 at.%）的BET面积为102 m~2/g,孔尺寸大小约为9.8 nm,具有比P25更强的光催化降解甲基橙的能力。

英文摘要：

N-doped mesoporous TiO_2 was prepared via a facile sol-gel route catalyzed by citric acid,and N-TiO_2 was characterized using powder X-ray diffraction（XRD）,High-resolution transmission electron microscope（HRTEM）,X-ray photoelectron spectrum（XPS）,N_2 adsorption（BET）,UV-xis diffused reflectance spectra（UV-vis）.The results revealed that uncalcined N-TiO_2 was amorphous,and the products calcined under lower temperatures were anatase,while the one annealed at 750℃was rutile The doping of a little N element resulted in a red shift of the absorption edge,shifting to the visible light region of mesoporous TiO_2.N_2 adsorption isotherm showed that the BET surface area and the average pore size of N-doped TiO_2 were about 102 m~2/g and 9.8 nm,respectively.Compared with P25 TiO_2,N-doped mesoporous TiO_2 exhibited improved photocatalysis activities for photodegradation of methyl orange.