Ag/BiOX (X=Cl,Br, I)复合光催化剂的制备、表征及其光催化性能

采用光化学沉积法制备了一系列不同Ag含量的新型Ag/BiOX(X=Cl,Br,I)复合光催化剂,应用X射线粉末衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)、光致发光(PL)谱、紫外-可见(UV-Vis)光谱和N2物理吸附等手段对催化剂进行表征,并以420nm<λ<660nm的可见光为光源,评价了该催化剂光催化降解酸性橙II的活性,考察了不同含量的Ag沉积对BiOX样品光催化性能的影响.N2物理吸附测试结果表明,沉积银在一定程度降低了催化剂的比表面积.UV-Vis测试结果表明,Ag能产生表面等离子共振吸收,有效增强BiOCl和BiOBr对可见光的吸收能力.PL测试结果则表明,Ag能显著抑制光生电子(e-)和空穴(h+)的复合.Ag的存在大幅度提高了BiOX对染料的光催化降解活性.当负载Ag的质量分数(w)为1%-2%时,可使BiOCl、BiOBr和BiOI光催化活性分别提高了10、13和2倍.Ag/BiOX复合光催化剂具有更高催化活性的原因是复合光催化剂对可见光有很强的吸收能力,同时产生了银等离子体光催化作用和银抑制了Ag/BiOX(X=Cl,Br,I)的光生电子-空穴的复合.

Preparation,Characterization and Photocatalytic Performance of Ag/BiOX(X=Cl,Br,I)Composite Photocatalysts

A series of novel bismuth oxyhalide Ag/BiOX(X=Cl,Br,I)composite photocatalysts were synthesized by a solution-based photodeposited method at room temperature.The resulting products were characterized by powder X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),photoluminescence(PL)emission spectroscopy,UV-Vis diffuse reflectance spectroscopy(DRS),and N 2 physical adsorption.The photocatalytic activity of the samples was evaluated by photocatalytic degradation of acid orange II under visible light(420 nm<λ<660 nm)irradiation.Analysis by N 2 physical adsorption showed that deposition of Ag decreased the specific surface area of the catalyst. UV-Vis DRS analysis indicated that the presence of Ag could result in surface plasmon absorption, effectively increasing the visible light absorption ability of BiOCl and BiOBr.Furthermore,PL analysis indicated that Ag could effectively suppress the recombination of photogenerated electron(e - )-hole(h + ) pairs of Ag/BiOX.Activity testing indicated that the deposition of an optimal amount of 1%-2%(w,mass fraction)Ag brought about 10,13,and 2 fold increases in the photocatalytic activity of BiOCl,BiOBr,and BiOI,respectively.The high photocatalytic performance of the composite photocatalysts could be attributed to the strong visible light absorption,silver plasmon photocatalysis role and the recombination restraint of the e - /h + pairs resulting from the presence of metal silver particles.