Template-free synthesis of mesoporous Mn3O4-Al2O3 catalyst for low temperature selective catalytic reduction of NO with NH3

Abstract

Abstract Mesoporous Mn3O4-Al2O3 catalyst with highly dispersed Mn3O4 and a high surface area is prepared using a one-pot synthesis technique without any templates. The synthesis procedure is environmentally friendly due to the low concentration of residual metal ions in the filtered solution, which allows for its direct release without further processing. The results show that the presence of Mn2+ ions stabilizes the Al(OH)3 crystal phase during hydrothermal treatment and prevents the formation of the AlOOH phase otherwise observed in the absence of Mn2+ ions. Because of the high stability of the resulted Mn3O4-Al(OH)3 nanoplatelets, a mesoporous Mn3O4-Al2O3 structure was formed via the dehydration of the Al(OH)3 after high-temperature calcination. The catalytic efficiencies of the Mn3O4-Al2O3 catalysts in the low-temperature selective catalytic reduction of NO with NH3 are examined under various reaction temperatures in the range of 80–200 °C. The results show that the NO conversion reaches as much as 94% at a reaction temperature of 80 °C. The proposed synthesis method thus holds considerable promise for the green, low-cost and scalable production of highly mesoporous Al2O3-based catalysts.