Mn/SAPO-34 as an efficient catalyst for the low-temperature selective catalytic reduction of NO_x with NH₃

Abstract

A series of Mn-exchanged SAPO-34 catalysts were synthesized and developed as catalysts for the low temperature selective catalytic reduction (SCR) of NO with ammonia in the presence of excess oxygen.

The promotion effect of manganese on Cu/SAPO for selective catalytic reduction of NOx with NH3

“…Consistent with the H 2 -TPR result, the UV-vis results showed the partial oxidation of Mn 2+ to Mn 3+ or Mn 4+ , when manganese loading increased. The UV-vis spectra of xMn-2Cu/SAPO were similar to that of xMn/SAPO (x ¼ 1, 2, 4, 8) 14 in that the percentage of Mn 3+ increased suddenly as manganese loading increased from 2% to 4%, indicating that the distribution of manganese species might not have been inuenced by the copper species. Fig.…”

“…The E p prole was almost the same as the NO conversion prole, indicating that the increase in NO oxidation activity would promote the lowtemperature SCR activity. Compared with the xMn/SAPO (x ¼ 1, 2, 4, 8) previously prepared, 14 the NO oxidation activities of xMn-2Cu/SAPO were much higher, which could be one reason for the increased SCR activity.…”

“…As manganese loading reached 8%, the diffraction peaks of the Mn 2 O 3 phase appeared, indicating the aggregation of manganese species and decreased manganese dispersity. On xMn/SAPO (x ¼ 1, 2, 4, 8), which was previously prepared, 14 there too were no peaks attributed to manganese oxides until manganese loading increased to 8%. Fig.…”

“…17 The shapes of 1Mn-2Cu/SAPO, 2Mn-2Cu/SAPO and 4Mn-2Cu/SAPO were similar while the activity differed a lot, indicating that the related acid sites might not have signicant inuence on the SCR activity for xMn-2Cu/SAPO. For xMn/ SAPO (x ¼ 1, 2, 4, 8), 14 the amount of ammonia desorption also decreased as manganese loading increased.…”

Recent advances in the selective catalytic reduction of NO<sub><italic>x</italic></sub> by NH<sub>3</sub> over small-pore zeolite catalysts

“…Pang等 [61] 对Mn/SAPO-34进行了研究, 发现Mn可 The NO conversions at 593 K over fresh and aged catalysts are given as a bar diagram (color online) [55] 图 13 Fe/SSZ-13在NH 3 -SCR反应活性位点(网络版彩图) [58]…”