N、Fe共掺杂纳米TiO2的制备和性能

以钛酸丁酯为钛源,用醇热法制备了N、Fe单掺杂及共掺杂纳米TiO₂。对样品的晶型结构、表面形貌、比表面积、紫外可见吸收、光致发光和分解水制氢催化性能分别进行了表征。结果表明,在500℃退火的N、Fe共掺杂TiO₂样品均为锐钛矿相棱形纳米颗粒,分散性较好,平均粒径约20 nm;N、Fe共掺杂的摩尔分数分别为5.0%和2.0%时,样品具有良好的可见光吸收活性,对光的吸收从387 nm（未掺杂锐钛矿相TiO₂）红移至510 nm处。主要原因可能是,N和Fe共掺杂在其禁带中产生杂质能级,导致其禁带宽度减小;N、Fe单掺杂及共掺杂改性,有效抑制了电子-空穴的复合,提高了光生载流子的分离效率;在可见光下（λ>400 nm）N、Fe共掺杂TiO₂具有较高的光催化分解水制氢活性,氢气生成速率为299.2μmol·g^-1·h^-1。

Preparation and Properties of N and Fe Codoped Nano TiO2

Pure nano TiO₂,N doped,Fe doped,and N and Fe co-doped nano TiO₂ were prepared by alcohol-thermal method using butyl titanate as Ti sources.Its crystal structure,surface morphology, specific surface area,UV-Vis.absorption,photoluminescence and photo-catalytic activities of hydrogen evolution were characterized.The results show that all the TiO₂ samples own a pure anatase phase with the average diameter of about 20 nm after calcinations at 500℃,and distribute uniformly as the prismatic type of particles.N and Fe co-doped TiO₂ exhibits higher visible light activity,the optimal doping amount of N and Fe is 5.0%and 2.0%respectively,which can make the absorption wavelength of TiO₂ shift to 510nm compared with that of pure TiO₂.N and Fe co-doping can generate the impurity levels in the band gap of TiO₂,leading to a good visible light response.The recombination of photo-excited electrons and holes is restrained by N and Fe co-doping.N and Fe co-doped TiO₂ displays higher catalytic activity under visible light irradiation（A>400 nm）,the hydrogen evolution rate is 299.2μmol·g^-1·h^-1 by water splitting.