Fe2O3/氮掺杂石墨烯复合材料的热分解动力学

Kinetic study of the thermal decomposition of Fe2O3/nitrogen-doped graphene(NG)composites

对Fe2O3/氮掺杂石墨烯(NG)的热解行为进行热重研究,分析出物质的热分解特性和机理函数。通过水热法制备Fe2O3/NG样品,在氮气氛围的保护下分别以5、10、15、20 K/min的升温速率线性升温到1473.15 K。使用Kissinger Akahira and Sunose(KAS)、Flyn n-Wal l-Ozawa(FWO)两种“model free”方法和Coat s-Redfern模型拟合法进行热动力学拟合,结果表明:FWO和KAS两种拟合法估算的表观活化能变化范围分别为404.08~424.65 kJ/mol和405.52~427.10 kJ/mol,且表观活化能随着转化率的增大而增加;FWO和KAS两种拟合法估算的表观活化能平均值分别为410.92 kJ/mol和412.74 kJ/mol,相差0.4%;Mample Power(P3)是最能反映Fe2O3/NG分解机理的函数。

The thermal decomposition behavior of Fe2O3/nitrogen-doped graphene(NG)composites,a potential anode material for supercapacitors,has been investigated by TG analysis.The Fe2O3/NG samples were prepared by a hydrothermal method,with the temperature increased to 1473.15 K at different heating rates of 5,10,15 and 20 K/min under nitrogen.The thermal decomposition characteristics of the composites and the reaction mechanism were analyzed.“Model-free”methods including the Kissinger-Akahira-Sunose(KAS)method and the Flynn-Wall-Ozawa(FWO)method and the Coats-Redfern model fitting method were employed to estimate key parameters.For the FWO and KAS methods,the activation energies increase monotonically from 404.08 kJ/mol to 424.65 kJ/mol and 405.52 kJ/mol to 427.10 kJ/mol,respectively.The average activation energies values for the two cases are 410.92 kJ/mol and 412.74 kJ/mol,respectively,with a discrepancy of 0.4%.The Mample Power(P3)rule best reflects the dynamics of the true chemical process in the Fe2O3/NG decomposition reaction.