钴掺杂对草酸锌热分解过程的影响

摘要

在空气气氛下,利用热重/差热扫描同步热分析仪(TG/DSC),对掺钴草酸锌(CoxZn1-xC2O42H2O(摩尔分数x为0和5％))的热分解过程及其动力学进行分析.动力学分析采用多升温速率法,通过Fredman方程和OFW方程2种不同方法对活化能和指前因子进行计算,考察钴掺杂对整个过程的影响.实验结果表明:钴掺杂使草酸锌热分解反应的热量变化由吸热变成放热;随着钴的掺入,反应的活化能降低,即钴掺杂使反应的难度降低;用多元线性回归方法确定的活化能分别为E=178.5 kJ/mol(x=0)和 E=150.0 kJ/mol (x-5％),最可几机理函数均为Cn(自催化反应)模型.%The thermal decomposition process and kinetics of CosZni-xC2O4.2H2O (molar fraction x is 0 and 5%, respectively) were investigated by TG/DSC in the atmosphere of stastic air, and the effect of cobalt doping on this process was analyzed. The pre-exponential factor and the activation energy were calculated by the Fredman equation and OFW equation considering the multi-heating rate method. The results show that cobalt doping makes the heat flow turn from endothermic to exothermic. The activation energy decreases as the result of cobalt doping which means the reaction difficulty reduces. The most possible mechanism is Cn (self-catalysis) when x=0 and x=5%, and the values of activation energies are E=178.5 kJ/mol (x=0) and E=150.0 kJ/mol (x=5%) determined by multiple linear regression, respectively.