Thermal behavior of Mg–Al–CO3 layered double hydroxide characterized by emanation thermal analysis

Abstract

Abstract Emanation thermal analysis (ETA) was used to characterize microstructure changes during heating of Mg–Al–CO3 layered double hydroxide (LDH) in the temperature range of 293–1473 K. It was confirmed by ETA that the formation of an intermediate phase with grafted CO32– anions in the hydroxide layers took place in the temperature range of 508–523 K and the formation of Mg–Al mixed oxide (MO) occurred in the range 623–773 K. The small peak of the emanation rate at 603 K indicated the degradation of the layered structure and the broad peak in the range of 1073–1273 K characterized the onset of the separation of the decomposition products of MO into MgO and Mg2Al4O7. The ETA results revealed that dehydration of the product with grafted CO32– anions occurred at lower temperatures than that of the initial Mg–Al–CO3 LDH.