植物膜模板法合成二维超薄纳米片及其光催化性能研究

The synthesis of two-dimensional ultrathin nanosheets by using plant membrane as template and photocatalytic performance

以山茶花花瓣为模板,经硝酸铈溶液浸渍后煅烧,合成新型超薄CeO2分层介孔纳米片。采用X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、原子力显微镜(AFM)、紫外-可见漫反射光谱(UV-Vis/DRS)、X射线光电子能谱(XPS)和氮气吸附-脱附等分析手段对样品进行了表征。结果表明所得样品是由厚度约为6nm的具有生物形态结构的萤石结构CeO2纳米片组成。制得的CeO2薄层表面存在大量介孔,其孔径集中分布于15nm左右。由紫外-可见漫反射吸收光谱可知,材料的吸收边较块体CeO2红移了约35nm,从而具有了更高的可见光催化活性。在阳光照射下表现出了较强的光催化活性,在90min内对亚甲基蓝的降解率可达98%,远高于普通块体CeO2。

Hierarchical mesoporous CeO2 nanosheets were prepared by using camellia flower petal as biotemplate through thermal decomposition.For characterization of texture,X-ray diffraction spectroscopy (XRD),field emission scanning electron microscopy (FESEM),transmission electron microscopy (TEM),atomic force mi-croscope (AFM),UV-Vis diffuse reflectance spectra (UV-Vis/DRS)and nitrogen adsorption-desorption meas-urements were adopted.The results demonstrated that the biomorphic structure of fluorite structure CeO2 nanosheets with the thickness of 6 nm was obtained.There existed mesopores with pore size of about 1 5 nm on the surface of the CeO2 nanosheets.Hierarchical mesoporous CeO2 nanosheets exhibited a clear red shift (35 nm)comparing with bulk CeO2 ,which could be excited by visible irradiation and enhance the visible activity. Hierarchical mesoporous CeO2 nanosheets display the superior photocatalytic activity for the degradation of methylene blue under sunlight irradiation,with a degradation rate as high as 98%.It was contributed to the smaller crystallite size,enhanced higher surface area of the ceria nanosheets.