A study on the preparation of Cr2O3 from (NH4)2Cr2O7 based on thermal decomposition including the thermal decomposition temperature effect, mechanism and kinetics

In this study, the thermal decomposition process of (NH4)2Cr2O7, including the effect of thermal decomposition temperature on the physicochemical properties of products, thermal decomposition mechanism, and kinetics, was studied in detail. The phase compositions, crystal structures, and micromorphology of thermal decomposition products were determined based on XRD and SEM analysis. The effect of thermal decomposition temperature on particle size, specific surface area, and chromaticity was investigated systematically. The lowest thermal decomposition temperature was determined, and the reaction equations were conjectured. The thermal decomposition mechanism of (NH4)2Cr2O7 was further revealed at the molecular level using FT-IR analysis and DFT calculation. At last, Kissinger and Kissinger-Crane methods calculated the kinetic parameters of (NH4)2Cr2O7 thermal decomposition, and the rate equation was established.