采用共沉淀法在不同母盐溶液浓度条件下合成出Gd2Ti2O7∶Ce纳米粒子;用XRD、SEM、TG-DTA等测试手段分析了样品的物相、形貌及发光性能;用热分析动力学计算不同升温速率下样品的活化能.结果表明:前驱体在升温过程的物相变化分3个阶段,用Doyle-Ozawa和Kissinger法分别对初始浓度为0.08和0.04 mol/L条件下各阶段表观活化能进行计算,其平均值为42.43、145.58、381.98 kJ·mol-1和51.28、161.51、446.30 kJ·mol-1,晶粒生长活化能分别为12.58和19.54 kJ·mol-1.浓度为0.08 mol/L时,1173 K煅烧2h制备出的纳米粒子表面活性较高,铈离子掺杂0.7％(摩尔分数)时发光强度最大.
Gd2Ti2O7∶Ce nanoparticles were prepared under different initial solution concentrations by a co-precipitation method.The phase composition,particle morphology and luminescence properties of the samples were characterized by XRD,SEM and TG-DTA,respectively.Their thermal analysis kinetics and activation energy in the synthesis process were also calculated at different heating rates.Results show that there arethree stages in the process of the precursor's phase transformations during heating.When the initial solution concentrations are 0.08 mol/L and 0.04 mol/L,the average apparent activation energies of the three reaction stages of precursors are 42.43,145.58,381.98 kJ·mol-1 and 51.28,161.51,446.30 kJ.mol-1,respectively,calculated by the Doyle-Ozawa and Kissinger methods.Meanwhile,the grain growth activation energies of the two concentrations 0.08 mol/L and 0.04 mol/L are 12.58 kJ·mol-1 and 19.54 kJ·mol-1,respectively.It is concluded that nanoparticles with higher surface activity have the best luminescence property when calcined at 1173 K for 2 h,especially the samples doped with 0.7 mol％ Ce is optimal at the concentration of 0.08 mol/L.
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