大颗粒氧化铈的草酸盐前驱体热分解研究

Study on the Thermal Decomposition of Cerium Oxalate Precursor of Large Particle CeO_2

用XRD研究了前驱体和不同灼烧温度下产物的物相,用SEM研究了最佳灼烧条件所得产物的形貌,用TG-DSC法研究了大颗粒氧化铈的草酸盐前驱体的热分解过程。采用Freeman-Carroll法研究了大颗粒氧化铈的草酸盐前驱体的热分解动力学行为。同时用Satava法进行了反应机理推断,草酸铈的分解反应分两阶段进行,第一阶段反应的E=68.6kJ.mol-1,第二阶段反应E=377.725kJ.mol-1,反应速率常数分别是K398K=2.576×10-4,K588K=5.264×10-2。

The XRD was used to study phase of precursor and product of large particle CeO2 ignited under different temperatures;SEM was used to study morphorlogy of product ignited at optimum temperature;TG-DSC was used to study the thermal decomposition dynamics and composition.Freeman-Carroll were used to study thermal decomposition dynamic of cerium oxalate precursor.The reaction mechanism derived from Satava method and it proves that decomposition reaction of Ce2（C2O4）3·8.5H2O was in two steps.The activation energy of first step is 68.6kJ·mol-1,the activation energy of second step is 377.725kJ·mol-1.The reaction rate constant K398k is 2.576×10-4 and K588k is 5.264×10-2 respectively.