Influence of calcination temperature on Fe0.8Mg0.2Oz catalyst for selective catalytic reduction of NOx with NH3

Abstract

A series of Fe0.8Mg0.2Oz catalysts for selective catalytic reduction (SCR) of NOx with NH3 were prepared via co-precipitation method with microwave thermal assistant at different calcination temperature. The influence of calcination temperature on the catalytic performance, microstructure properties, surface elements and acidity over Fe0.8Mg0.2Oz-T catalysts was investigated by various characterization methods. Fe0.8Mg0.2Oz catalyst calcined at 400 °C showed the highest NOx conversion and excellent N2 selectivity. More than 90% NOx conversion could be achieved in a wide temperature range of 250–350 °C. Fe0.8Mg0.2Oz-400 with large surface area and pore volume obtained a high purity γ-Fe2O3 crystalline phase with the calcination temperature of 400 °C. Meanwhile, Magnesium had strong interaction with γ-Fe2O3 and existed in either highly dispersed or amorphous phase. Surface oxygen concentration and acidity (mainly Brönsted acid sites in Fe0.8Mg0.2Oz-T catalysts) played an important role in SCR reaction. The results implied that the higher surface area, pore volume, strong interaction, superior surface acidity and redox ability contributed to the excellent SCR catalytic performance of Fe0.8Mg0.2Oz catalyst calcined at 400 °C.