Tunable preparation of highly dispersed Ni x Mn-LDO catalysts derived from Ni x Mn-LDHs precursors and application in low-temperature NH 3 -SCR reactions.

A series of Ni x Mn bimixed metal oxides (Ni x Mn-LDO) were prepared via calcining Ni x Mn layered double hydroxides (Ni x Mn-LDHs) precursors at 400 °C and applied as catalysts in the selective catalytic reduction (SCR) of NO x with NH 3 . The DeNO x performance of catalysts was optimized by adjusting the Ni/Mn molar ratios of Ni x Mn-LDO precursors, in which Ni 5 Mn-LDO exhibited above 90% NO x conversion and N 2 selectivity at a temperature zone of 180-360 °C. Besides, Ni 5 Mn-LDO possessed considerable SO 2 & H 2 O resistance and outstanding stability. Multiple characterization techniques were used to analyze the physicochemical properties of the catalysts. The analysis results indicated that all catalysts had the same active species Ni 6 MnO 8 , while their particle sizes showed significant differences. Notably, the uniform distribution of active species particles in the Ni 5 Mn-LDO catalyst provided the rich surface acidity and suitable redox ability which were the primary causes for its desirable DeNO x property.