Kinetic study on the thermal decomposition of layered double hydroxides

The thermal decomposition of layered double hydroxides (LDH) influences the preparation of composite oxides by calcination of LDH precursors. The thermal decomposition of LDH with different Mg/Al ratios was measured using thermalgravimetric analysis and differential temperature analysis. The kinetic data for the thermal decomposition was also calculated. The initial Mg₂Al-LDH and the calcination products at various temperatures were characterized by X-ray diffraction and IR spectroscopy. The results show the evolution of carbonates in the interlayer between 250°C and 700°C, with the main evolution at 330-400°C. New materials were produced by decarbonation and dehydroxylation of OH bound with the sheet. The LDH decomposed to mixed oxides upon heating to 500-700°C.