Pd纳米粒子对BiOBr的光吸收和光催化性能的影响

首先合成高结晶度的BiOBr纳米片，然后利用光化学气相沉积（PCVD）法将不同含量的Pd纳米粒子沉积在BiOBr纳米片上．运用N，一物理吸附．脱附、x射线粉末衍射（XRD）、透射电镜（TEM）、x射线光电子能谱（xIX3）、光致发光（PL）谱、紫外可见漫反射吸收光谱（uV-VisDRS）技术对合成的Pd／BiOBr进行了表征．考察了Pd含量对BiOBr光吸收性能和紫外光（A=254am）、可见光下对染料酸性橙Ⅱ的光催化降解性能的影响．结果表明，沉积Pd对样品的比表面积影响不大，Pd纳米粒子能在一定程度上增强催化剂对可见光的吸收能力，并显著抑制光生电子和空穴的复合．紫外光下，当Pd的质量分数为0．5％时，BiOBr催化降解染料的活性提高到1．6倍，而在可见光下含4％的Pd能使BiOBr表现出最高的催化活性，为纯BiOBr的1．5倍．

Effects of Pd Nanoparticles on Light Absorption and Photocatalytic Performance of BiOBr

BiOBr nanoplates with high crystallinity were first synthesized. Then, Pd nanoparticles with different contents were deposited over BiOBr via photochemical vapor deposition （PCVD） method. The prepared products were characterized by N2-physical adsorption-desorption, X-ray diffraction （XRD）, transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS）, photoluminescence emission （PL） spectroscopy, and UV-Vis diffuse reflectance spectroscopy （DRS）. The effects of Pd con centration on light absorption and photocatalytic activity of BiOBr in degradation of acid orange 11 were evaluated under both UV light （A = 254 nm） and visible light irradiation. The N2-physical adsorption test shows that the presence of Pd nanoparticles could not obviously change the specific surface area of the catalyst. The UV-Vis DRS results indicate that Pd nanoparticles could slightly shift the light absorption edge of BiOBr to long wavelength direction. PL spectra suggested that Pd could suppress the recombination of photogenerated hole-electron pairs. Under UV light irradiation, Pd 0. 5% （mass fraction） with loading can increase the photocatalytic activity of BiOBr by 60% , while under visible light irradiation,4% is found to be the optimum content of Pd, which results in an increase of 50% in photocatalytic ac- tivity.