NOx Removal Performance Optimization of NiMnTi Mixed Oxide Catalysts by Tuning the Redox Capability

Abstract

AbstractA series of Ni4‐xMnxTi1Oy mixed metal oxides (Ni4‐xMnxTi1‐LDO) catalysts originated from layered double hydroxides (LDHs) were fabricated and evaluated in the selective catalytic reduction of NO with NH3 (NH3‐SCR). To optimize the denitrification performance, the redox capability of catalysts was adjusted by calcining the Ni4‐xMnxTi1‐LDHs precursors with different Mn loading at different temperatures. The results revealed that calcination temperature was the secondary factor while the molar ratio of Mn to Ni was the main factor for influencing the redox properties. Among Ni4‐xMnxTi1‐LDO catalysts, the Ni2Mn2Ti1‐LDO catalyst afforded the optimal DeNOx behavior with above 90 % NOx conversion and 95 % selectivity of N2 as well as superior SO2 resistance in the wide temperature region of 150–360 °C. Multiple characterizations indicated that exceptional catalytic performance of Ni2Mn2Ti1‐LDO catalyst was highly dependent on the suitable redox capability resulted from moderate concentration of Ni3+, Mn4+ and chemisorbed oxygen Oβ in catalysts surface.