Nanoscale Co3O4 powders prepared by an enhanced solid-state reaction method

Abstract

This work is focused on the mechanism study of nanoscale Co3O4 powders prepared by an enhanced solid-state reaction method. The as-prepared powders are characterized by thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with the powders ball milled for different times as the control. The results show that ball milling can accelerate the thermal decomposition process by approximately 18.2%. Moreover, the apparent thermal decomposition activation energy of CoCO3 powders pretreated by the enhanced solid-state method declined by 33.2%. To elucidate this,the thermal decomposition kinetic equations of CoCO3 powders, with and without ball milling, are calculated. And the thermal decomposition kinetic equation of the ball-milled powders is dα/dt = (2.42E6~2.19E7) exp [(8.74E3~9.96E3)/T] 4/3(1-α) [-ln(1-α)]1/4; while that of the powders lack of ball milling is dα/dt = (1.08E10–1.07E11) exp [(1.43E4~1.51E4)/T] 2/3α−1/2, respectively. The reaction process at different time points can be forecasted by the obtained equations.