Tunable preparation of highly dispersed NixMn-LDO catalysts derived from NixMn-LDHs precursors and application in low-temperature NH3-SCR reactions

摘要

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) andH _(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.