Low-temperature SCR of NOx with NH3 over manganese oxides supported on multiwalled carbon nanotubes

A series of manganese oxide catalysts supported on Multiwalled Carbon Nanotubes (MWNT) were prepared by a wet impregnation method for Low-Temperature (373-573K) Selective Catalytic Reduction (LTSCR) of NOx with NH3 in the presence of excess O2. These catalysts werecharacterized by N2 adsorption, transmission electron microscopy, fourier transform infraredspectroscopy and inductively coupled plasma methods .The effects of reaction temperature,oxidation of support, and MnOx loading were investigated. The beneficial effect of support oxidation was demonstrated. The MnOx/Oxidized-MWNT catalysts showed good activities in LTSCR of NOx with NH3. NOx conversion varied in a wide range depending on MnOx loading.The selectivity to N2 decreased in a small range by increasing of MnOx loading. Under the reaction conditions of 483K, 1 bar, NO/NH3=1, GHSV=30000hr-1, and 12% wt MnOx/Oxidized- MWNT, NOx conversion and N2 selectivity of 90% & 99% were obtained, respectively.

Keywords:

LTSCR , multiwalled carbon nanotubes , MnOx , wet impregnation , NOx