TiO_2掺杂粉体的溶胶-凝胶和水热合成及其光降解甲醛(英文)

PHOTODEGRADATION OF FORMALDEHYDE OF DOPED TITANIA NANOCRYSTALS PREPARED BY SOL-GEL SYNTHESIS AND HYDROTHERMAL PROCESSING

为了研究不同掺杂对二氧化钛光化学活性的影响,采用溶胶-凝胶,水热法,由TiOCl2成功制备了掺杂氮原子的二氧化钛样品,并制备了掺杂0.5%(摩尔分数)Fe3+,Cu2+,V5+,Pd2+等金属离子的可见光响应型介孔材料。样品经由X射线衍射,透射电镜,Brunauer-Emmett-Teller(BET)比表面积,Barrett-Joyner-Halenda孔径分布,紫外可见光谱,光电子能谱和荧光光谱等表征;以荧光灯为光源(入射光波长λ≥410nm),光催化降解甲醛为模式,评价了样品的催化活性。结果表明:掺杂Fe3+,Cu2+,V5+,Pd2+的二氧化钛和单一掺氮的二氧化钛样品的粒径均为10nm左右,BET比表面积为130m2/g左右,均为锐钛矿相二氧化钛;Fe/TiO2,Cu/TiO2,V/TiO2,Pd/TiO2和TiO2/N样品的带隙能依次为:2.99,2.93,2.36,2.92eV和2.87eV,其在可见光下的光催化降解速率常数分别为:0.0063,0.0086,0.0049,0.0031/min和0.0033/min。Cu/TiO2较高的荧光强度和较大的比表面积,导致了其较高的可见光光解活性。

Titania particles doped with nitrogen were sol-gel and hydrothermaUy synthesized in an autoclave from TiOCI2. Mesoporous titania with 0.5% （in mole） Fe^3＋, Cu^2＋, V^5＋ and Pd^2＋ as dopants were also prepared based on the above synthesis method. The structure of the samples was characterized by X-ray diffraction, transmission electron microscopy, the Brunauer-Emmett-Teller （BET） specific surface area, the Barrett-Joyner-Halenda pore size distribution, ultraviolet-visible spectroscopy measurements and photoluminescence. The photocatalytic activity was investigated under visible light irradiation （2/〉410 nm）, and formaldehyde was taken as the test gas. It is found that the prepared samples are anatase titania with average grain sizes of about 10 nm and BET specific surface areas of about 130 m2/g. The band gap of the titania samples doped with Fe^3^, Cu^2＋, V^5＋, Pd^2＋ and TiO2/N is 2.99, 2.93, 2.36, 2.92 eV and 2.87 eV, respectively. The photo-degradation rate constant of titania samples with 0.5% （in mole） Fe^3＋, Cu^2＋, V^5＋ and Pd^2＋ doping and TiO2/N is 0.0063, 0.0086, 0.0049, 0.0031/min and 0.0033/min, respectively. Good dispersion of Cu^2＋ dopant onto the surface of titania, adequate surface area and decrease of recombination center on the surface of Cu/TiO2 photocatalyst may contribute to its comparatively higher photocatalytic activity.