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

A series of Ni Mn bimixed metal oxides (Ni Mn-LDO) were prepared calcining Ni Mn layered double hydroxides (Ni Mn-LDHs) precursors at 400 °C and applied as catalysts in the selective catalytic reduction (SCR) of NO with NH. The DeNO performance of catalysts was optimized by adjusting the Ni/Mn molar ratios of Ni Mn-LDO precursors, in which NiMn-LDO exhibited above 90% NO conversion and N selectivity at a temperature zone of 180-360 °C. Besides, NiMn-LDO possessed considerable SO & HO 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 NiMnO, while their particle sizes showed significant differences. Notably, the uniform distribution of active species particles in the NiMn-LDO catalyst provided the rich surface acidity and suitable redox ability which were the primary causes for its desirable DeNO property.