Gd^3+掺杂ZnO的制备及其性能

Preparation and Performance of Gd^3+-Doped ZnO

为提高ZnO的光催化性和稳定性,扩展对光的吸收范围,以乙二胺四乙酸(H4EDTA)为配体形成配位前驱体,通过低温热分解配位前驱体法制备了Gd 3+掺杂ZnO复合物Zn1-xGdxO2(x=0~0.1)纳米颗粒。采用X射线粉末衍射(XRD)、红外光谱法(FT-IR)、扫描电子显微镜(SEM)、荧光光谱法(FL)、紫外可见漫反射光谱法(UV-Vis DRS)、交流阻抗(EIS)以及动态光电流响应(i-t)等多种手段研究掺杂比例对氧化锌物相、表面形貌、光学性以及光电响应性等的影响。结果表明,Gd^3+掺杂摩尔分数低于3%时,产物为单相纤锌矿ZnO,提高掺杂比例(>3%)不仅使ZnO晶格萎缩,同时还出现少量Gd2O3第二相,且晶粒随掺杂摩尔分数的增加而降低。Gd^3+掺杂使ZnO能带结构发生改变,其价带、导带和带隙等各值都随着掺杂摩尔分数的增加而降低。I-t结果表明,适量掺杂可提高ZnO的光电响应能力,其中掺杂摩尔分数1%所得ZnO的光电流密度最大(10 mA/m^2)。甲基橙(MO)的光降解结果显示,Gd^3+掺杂能提高ZnO的催光化性,其中1%掺杂对ZnO的催化性提高最大。最后还对ZnO的催化选择性和耐酸碱性进行了简单研究。

In order to improve photocatalytic activity and acid-resistant alkalinity of ZnO and expand the absorption range of light,nanosized ZnO particles doped with Gd^3+(Zn1-xGdxO2(x=0~0.1))were synthesized by thermal decomposition of the coordinated precursor,in which ethylenediamine tetraacetic acid(H 4 EDTA)is the ligand.Effects of the doping amount of Gd^3+ on the structure,phase,morphology,optical properties and photo-electrical behaviors of ZnO were studied by X-ray diffraction(XRD)spectrometry,ultraviolet-visible diffuse reflection spectroscopy(UV-Vis DRS),Fourier transform infrared(FT-IR)spectroscopy,flurescence spectroscopy(FL),scanning electron microscopy(SEM),electrochemical impedance spectroscopy(EIS),dynamic photoelectrical current curve(i-t),etc.XRD results show that when the amount of Gd^3+ is below 3%,there is a single phase of ZnO with hexagonal wurtzite structure.With the increase of Gd^3+ doping(>3%),a little bit of second phase of Gd2O3 shows up and the grain size of ZnO is reduced.From i-t results,Gd^3+ doping amount of 1%exhibits the biggest current density of 10 mA/m^2.With the increase of Gd^3+ doping,the band structure of ZnO is changed,the value of conduction band(CB),valence band(VB)and band-gap value(Eg)of ZnO are all reduced.At the same time,photo-degradation results of methyl orange(MO)reveal that Gd^3+ doping can enhance the photocatalytic activity of ZnO,and the suitable amount is 1%.The catalytic selectivity and acid-resistant alkalinity of ZnO and Gd-doped ZnO were also studied simply.