Influence of La(3+)-dopant on the Gain Size and Photocatalytic Performance of Nanometer ZnO PowdersWU Jian-feng,ZHAO Na,XU Xiao-hong,DENG Teng-fei,TIAN Yue (School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China)Pure nanometer ZnO and La3+-doped nanometer ZnO were synthesized from dihydrate zinc acetate by sol-gel method.Triammonium citrate was used as modifier.The characterization of powders was studied by X-ray diffraction(XRD) and transmission electron microscope(TEM).The results indicated that the pattern of nano-ZnO particles all belonged to hexagonal system.When the heat treatment was at 550 ℃,the smallest mean particle size of nano-ZnO was only 28.33 nm.ZnO grain size became smaller with the addition of lanthanum ions,and the doping content of 0.2% made the nanometer zinc oxide 7 nm decreased.Besides,lanthanum ion dopant increased the photocatalytic activity of nano-ZnO and the MB degradation increased by 30%—40%.La3+-dopant;nanometer ZnO;sol-gel;photocatalytic