Activity of mesoporous-MnOx (m-MnOx) and CuO/m-MnOx for catalytic reduction of NO with CO

The direct reduction of NO over mesoporous manganese oxide (m-MnOx) and in the presence of CO was studied at reaction temperatures in the range from 150 to 460 °C. The conversion of NO without the reducing agent CO was limited to less than 10%, but when CO was added to the reactor feed up to 70% of the NO was reduced at a reaction temperature of 340 °C. However, the m-MnOx catalyst activity deteriorated at temperature above 340 °C due to a transformation of MnO2 to the less active Mn2O3 and Mn3O4 phases. The activity of the m-MnOx catalyst at high temperatures was enhanced by the addition of CuO. Two methods to load CuO on the m-MnOx were investigated: wet impregnation and co-precipitation. Both methods produced catalysts that achieved close to 97% NO conversion in CO at a reaction temperature of 430 °C.

Graphical abstractThis figure outlines the activity of mesoporous MnOx and CuO supported on mesoporous MnOx synthesized by two different methods for removal of NO using CO as reducing agent.Figure optionsDownload full-size imageDownload high-quality image (104 K)Download as PowerPoint slideHighlights► Mesoporous MnOx studied for catalytic reduction of NO with CO. ► Above 340 °C, an irreversible phase change of MnO2 to Mn2O3 and Mn3O4 observed. ► The above phase change reduced the catalyst activity. ► Wet impregnation and co-precipitation methods used to synthesize CuO/meso-MnOx. ► CuO/meso-MnOx catalysts show superior activity at high temperatures.