Two-dimensional MnAl mixed-metal oxide nanosheets prepared via a high-shear-mixer-facilitated coprecipitation method for enhanced selective catalytic reduction of NO with NH3

Abstract

Mn-based mixed metal oxides (MMOs) have been considered to be low temperature denitration catalysts for selective catalytic reduction of NO with NH3. In this work, two-dimensional (2D) MnAl mixed-metal oxide nanosheets were successfully prepared via a high-shear-mixer-facilitated coprecipitation (HSM-CP) method. The as-obtained 2D MnAl-MMO achieved high specific surface area of 180.6 m2/g, average pore size of 9.8 nm and pore volume of 0.45 cm3/g. The as-obtianed MnAl-MMO (HSM-CP) catalysts performed superior NO conversion of 96.3% and N2 selectivity of 91% at 200 °C with a gas hourly space velocity (GHSV) of 30,600 h−1, all of which are much better than those of MnAl-MMO (CP). Even at 25 °C, the MnAl-MMO (CP) catalysts nearly had catalytic activity whereas MnAl-MMO (HSM-CP) achieved a better NO conversion of 40%. Moreover, MnAl-MMO (HSM-CP) catalysts performed excellent H2O and SO2 resistance, and NO conversion is still remained 75% at 200 °C with 5% H2O and 100 ppm SO2. HSM-CP provides a new strategy for the development of MMO as efficient denitration catalysts.