Role of the Mg/Al Atomic Ratio in Catalyst Support for NOx Storage/Reduction

Mg-Al-O catalyst support prepared by thermal decomposition of Mg/Al hydrotalcite precursors that obtained by coprecipitation method with different Mg/Al atomic ratios of 1.0, 2.0 and 3.0. The samples characterized by XRD and TG-DSC. The results show that the hydrotalcite performance have high crystallinity with the Mg/Al atomic ratio of 2:1 and 3:1; It can be clearly observed the diffraction peaks of MgO after calcined at 500 degrees C, and shows highest crystallinity of MgO with Mg/Al atomic ratio of 3:1, but we can't observed the diffraction peaks of Al2O3 because of high dispersity; TG-DSC analysis shows that hydrotalcite has chemical decomposed at 443 degrees C, and the quality lossed 32.97%, this indicates it transform the most of hydrotalcite into MgO at this temperature.