锡掺杂Bi2O3可见光响应光催化剂的制备及性能

以硝酸铋和四氯化锡为原料,采用浸渍法制备了纯Bi2O3和Sn掺杂Bi2O3光催化剂。利用X射线光电子能谱、X射线荧光光谱、X射线衍射、扫描电子显微镜、紫外-可见吸收光谱和光致发光光谱对样品进行了表征。在可见光下,利用2,4-二氯苯酚水溶液的光催化降解作为探针反应,考察了样品的可见光催化活性。结果表明,浸渍法能较好地实现Sn的掺杂,催化剂中掺杂剂Sn的价态为+4价,以锡的氧化物形式存在于Bi2O3晶格间隙或晶粒表面。并且掺杂适量的Sn,可有效抑制Bi2O3晶相由四方相向单斜相的转变,拓宽了Bi2O3的可见光响应范围,有效阻止了光生电子和空穴的复合,从而提高了Bi2O3的可见光催化活性。当Sn的掺杂量为2%时(物质的量的分数),Bi2O3具有最好的可见光催化活性。

Preparation and Properties of Tin-Doped Visible-Light-Responsive Bismuth Oxide Photocatalysts

Undoped and tin-doped bismuth oxide (Sn-Bi₂O₃) photocatalysts were prepared through impregnation method with bismuth nitrate and tin tetrachloride. The as-prepared samples were characterized by X-ray photoelectron spectroscopy (XPS), X-ray fluorescence spectrum (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectrophotometry (UV-Vis) and photoluminescence spectroscopy (PL). Under the irradiation of visible light, the photocatalytic properties of various samples were investigated by using degradation of 2, 4-Dichlorophenol solution (2, 4-DCP) as the probe reaction. The results show that the impregnation is a good doping method for the preparation of Sn-Bi₂O₃. And the valence state of doped Sn is +4, it presents in the form of tin oxide which disperses in the lattice gap or on the surface of bismuth oxide. The phase transformation of bismuth oxide from tetragonal to monoclinic can be effectively inhibited by an appropriate tin doping. Therefore, the photocatalytic activities of tin-doped bismuth oxide are improved as a result of the expanded visible-light region response and a lower recombination rate of electron/hole pairs. Furthermore, the bismuth oxide doped with 2% tin (in molar ratio) has the superior photocatalytic degradation efficiency for 2, 4-DCP.