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采用高温固相法合成了铈掺杂的K2La2Ti3O10催化剂,利用X射线衍射(XRD)、紫外-可见漫反射(UV-visDRS)、透射电镜(TEM)和X射线光电子能谱(XPS)对催化剂进行了表征.考察了催化剂的可见光催化分解甲醇水溶液制氢的活性,并对可见光催化机理进行了分析.研究表明,铈的掺杂没有改变K2La2Ti3O10的微晶结构,并使催化剂粒径有所减小.紫外可见漫反射分析表明禁带宽度为2.3eV左右,对可见光具有较高吸收.XPS表明La和Ti为+3和+4价,而Ce则是+3和+4的混合价态.担载2wt%Pt后,在可见光下光催化活性大大提高,当铈的掺杂量为0.5mol%(即Ce取代La的摩尔百分量)时,光催化活性达到最大,产氢速率为0.05mmol/h;光照5h后产氢量为0.22mmol,而纯K2La2Ti3O10的产氢量只有0.037mmol.
The cerium-doped K2La2Ti3O10 catalysts were synthesized by high temperature solid-state reaction. The catalysts were characterized by X-ray diffraction (XRD), UV-visDRS, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy The catalytic activity of visible light photocatalytic decomposition of methanol in aqueous solution was investigated.The mechanism of visible light photocatalysis was also studied.The results showed that the doping of cerium did not change the microcrystalline structure of K2La2Ti3O10 and decreased the particle size of the catalyst .Ultra-visible diffuse reflectance analysis shows that the bandgap width is about 2.3eV and has a higher absorption for visible light.XPS indicates that La and Ti are +3 and +4 valences, while Ce is a mixed valence state of +3 and +4. After 2wt% Pt was loaded, the photocatalytic activity increased greatly under visible light. When the doping amount of cerium was 0.5mol% (ie, the mole fraction of Ce substituted for La), the photocatalytic activity reached the maximum, and the hydrogen production rate was 0.05mmol / h. The amount of hydrogen produced after 5 hours of illumination was 0.22 mmol, while the pure hydrogen yield of pure K2La2Ti3O10 was only 0.037 mmol.