Activity and selectivity of pure manganese oxides in the selective catalytic reduction of nitric oxide with ammonia

Effect of manganese substitution on the structure and activity of iron titanate catalyst for the selective catalytic reduction of NO with NH3

“…4A. At the same time, the unselective oxidation of NH 3 would also get enhanced with the increasing of Mn 4+ /Mn 3+ ratio resulting in low N 2 selectivity in the SCR reaction, which was caused by the higher degree of hydrogen abstraction from ammonia by manganese species with higher oxidation state [7]. This is in accordance with the NH 3 oxidation results in Fig.…”

“…This pyrophanite compound would possibly be sintered to form compact oxide layer on the catalyst surface and make it difficult for the gaseous H 2 to diffuse into the inner bulk phase, thus leading to the delayed appearance of the small T 3 reduction peak. The total reduction process of MnTiO x is similar as the results over MnO x or MnO x /Al 2 O 3 in previous studies [7,60,61]. Moreover, it is noteworthy that the T 2 peak in MnTiO x delayed ca.…”

“…Manganese oxides usually show good SCR activity in the low temperature range, such as pure MnO x [7,8], MnO x loaded on TiO 2 / Al 2 O 3 /SiO 2 /AC (activated carbon) [9][10][11][12] and Mn-Ce, Mn-Cu mixed oxides [13][14][15]. Previous studies showed that in Fecontaining SCR catalysts, the introduction of Mn could obviously enhance the low temperature activity [16,17], probably due to the synergistic effect between iron and manganese species.…”

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

“…Wu et al [12] reported that the high oxidation state of Mn species was responsible for low N 2 selectivity over Mn-Ti oxide catalysts. Although the SCR activity of MnO 2 was higher than that of Mn 2 O 3 , the N 2 selectivity over the former sample was lower than that over the latter [19]. Therefore, the enhanced N 2 selectivity over the Mn 2 Nb 1 O x catalyst in the NH 3 -SCR reaction could be ascribed to the occurrence of Mn species with low oxidation state and also the decrease in the amount of Mn species.…”

Performance of Mn-based H2S sorbents in dry, reducing atmosphere – Manganese oxide support effects

“…The three step reduction of the supported Mn oxides was observed previously for the MnxOy-Al2O3 sorbents [11,30,40] and attributed to the reduction of MnO2 to MnO proceeding through Mn2O3 and Mn3O4 as indicated in the following sequence (4):…”