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

Abstract We report a novel NH 3 -SCR catalyst Cu 0.5 Mg 1.5 Mn 0.5 Al 0.5 O x synthesized from layered double hydroxides with superior activity in a wide temperature range and improved SO 2 and H 2 O resistance comparing to conventional doped Mn/γ-Al 2 O 3 . This catalyst results in a high NO x removal efficiency of 87.0–96.6% in the low temperature range of 100–250 °C, much better than Mn/γ-Al 2 O 3 (35.0–67.2%). Besides, it exhibits significant resistance to SO 2 and H 2 O 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 NH 3 -SCR activity of Cu 0.5 Mg 1.5 Mn 0.5 Al 0.5 O x catalyst can be associated with its high specific surface area, high reducibility of MnO 2 and CuO species, abundance of acid sites, and the well dispersion of MnO 2 and CuO species. The interactions between SO 2 and NH 3 , and the degradation mechanism caused by SO 2 were investigated using in-situ DRIFT analysis.