Preparation and Kinetics of the Thermal Decomposition of Nanosized CuC_2O_4-ZnC_2O_4 centre dot 2H_2O

摘要

The physical mixture of nanosized CuC_2O_4-ZnC_2O_4 centre dot 2H_2O, as precursors of CuO-ZnO, have been prepared by the one-step solid state reaction method at room temperature. The thermal decomposition processes taking place in the solid state oxalate mixture of nanometer CuC_2O_4-ZnC_2O_4 centre dot 2H_2O have been studied in static air using TG, DSC, XRD and TEM techniques. TEM showed that the grain size of the decomposition product is 5-15 nm. The values of the activation energy E_a were determined using the isoconversional procedure of KAS method and the Ozawa method. The most possible mechanism function f(a) of the thermal decompositions of nanosized CuC_2 O_4-ZnC_2 O_4 centr dot 2H_2O are defined using the comparative method, function models of the decomposition of CuC_2O_4 and ZnC_2O_4 follow the same mechanism function "Avrami-Erofeev equation". The pre-exponential factor A is obtained on the basis of E_a and f(a), thus the thermal analysis kinetic triplet of the decompositions of nanosized CuC_2 O_4 -ZnC_2O_4 centre dot 2H_2O are determined.