Synthesis of Cu0.5Mg1.5Mn0.5Al0.5Ox mixed oxide from layered double hydroxide precursor as highly efficient catalyst for low-temperature selective catalytic reduction of NOx with NH3.

We report a novel NH3-SCR catalyst Cu0.5Mg1.5Mn0.5Al0.5Ox synthesized from layered double hydroxides with superior activity in a wide temperature range and improved SO2 and H2O resistance comparing to conventional doped Mn/γ-Al2O3. This catalyst results in a high NOx removal efficiency of 87.0-96.6% in the low temperature range of 100-250 °C, much better than Mn/γ-Al2O3 (35.0-67.2%). Besides, it exhibits significant resistance to SO2 and H2O due to the existence of Cu and Mg. The promoting effects of Cu and Mg are thoroughly investigated using various physico-chemical techniques. The superior NH3-SCR activity of Cu0.5Mg1.5Mn0.5Al0.5Ox catalyst can be associated with its high specific surface area, high reducibility of MnO2 and CuO species, abundance of acid sites, and the well dispersion of MnO2 and CuO species. The interactions between SO2 and NH3, and the degradation mechanism caused by SO2 were investigated using in-situ DRIFT analysis.