Low temperature selective catalytic reduction of NO with NH3 over Mn–Fe spinel: Performance, mechanism and kinetic study

Manganese–niobium mixed oxide catalyst for the selective catalytic reduction of NOx with NH3 at low temperatures

“…After exposure to NH 3 , the catalysts were covered by several NH 3 species. The bands at 1604 and 1204 cm À1 were assigned to asymmetric and symmetric bending vibrations of the N-H bonds in NH 3 coordinately linked to Lewis acid sites, and the bands at 1428 and 1664 cm À1 were attributed to asymmetric and symmetric bending vibrations of NH 4 + species on Brønsted acid sites [28][29][30]. In the NH stretching vibration region of coordinated NH 3 , bands were found at 3342, 3254 and 3157 cm À1 [31].…”

“…11B. After NO + O 2 adsorption and N 2 purge, the sample surfaces were mainly covered by three types of nitrate, including monodentate nitrate (ˆ3 high at 1544 cm À1 ), bidentate nitrate (ˆ3 high at 1575 cm À1 andˆ3 low at 1280 cm À1 ), and bridging nitrate (ˆ3 high at 1622 cm À1 andˆ3 low at 1228 cm À1 ) [28,36,37]. On the MnO x catalyst, the intensity of NO x adsorption peaks were stronger than that on Mn 2 Nb 1 O x and NbO x catalysts, which is in accordance with the NO x -TPD results.…”

Effect of Mn substitution on the promoted formaldehyde oxidation over spinel ferrite: Catalyst characterization, performance and reaction mechanism

“…With the increase of Mn substitution in the spinel ferrites, the a 0 obviously increases, ascribed to the larger radius of Mn 3+ (0.72 Å) and Mn 4+ (0.67 Å) than that of Fe 3+ (0.64 Å) [46]. The a 0 variation indicates that Mn cations are incorporated into the spinel structure.…”

SNCR Application to Diesel Engine DeNOx under Combustion-driven Flow Reactor Conditions

“…Numerous studies for diesel NOx reduction have focused on the selective catalytic reduction (SCR) process by NH3/urea and hydrocarbons agents (i.e. searching for new catalysts), together with recent plasma-catalytic processes, but some practical problems like poor catalytic activities and lower NOx reduction (10~40%) have still emerged in actual exhaust gases (Masuda et al, 1996;Francke, 2000;Yang et al, 2011).…”