Radio-frequency (RF) plasma synthesis of H-ZSM-5 supported MnOx catalysts with high catalytic activity for deNOx-SCR by propylene

Traditionally, C3H6-SCR exhibited poor catalytic activity at low temperature (<300 degrees C) due to the difficult activation of C3H6. For investigation of the low temperature catalytic behavior of C3H6-SCR, a series of MnOx/ZSM-5 catalysts prepared by coprecipitation method was activated by an efficient H-2 RF plasma, and first used for C3H6-SCR. Under the simulated lean burn condition (5% O-2) of actual diesel engines, more than 99% NO conversion was observed at 200 degrees C-300 degrees C with the space velocity of 30000 If' on the MnOx/ZSM-5-H-2 RF-100W catalyst. Characterization results demonstrated that H-2 RF plasma activation could facilitate the growth of stronger active Mn2O3 species, and generated more lattice oxygen (O-beta) with a high electron cloud density. Besides, the stable BrOnsted acidity from uncoordinated framework Mn (Mn-O-Si), higher surface Mn concentration, good dispersion, and larger pore size caused by H-2 RF plasma could be also contribute to excellent low temperature C3H6-SCR catalytic activity. We expect this study to shed more light on the nature of the surface active sites of MnOx/ZSM-5-H2RF-100W in low temperature C3H6-SCR, and the development of novel preparation method for the synthesis highly-active catalysts of low temperature C3H6-SCR.

Automated summary

The MnOx/ZSM-5-H-2 RF-100W catalyst activated by efficient H-2 RF plasma exhibits excellent catalytic performance in low-temperature C3H6-SCR reactions, with over 99% NO conversion achieved at 200-300 degrees C under lean burn conditions. The improved catalytic activity can be attributed to the growth of stronger active Mn2O3 species, increased lattice oxygen, stable BrOnsted acidity, higher surface Mn concentration, good dispersion, and larger pore size facilitated by H-2 RF plasma activation.