LAUSR

OMS-2 catalysts exhibit excellent SCR activity at low temperature, but weak H2O resistance restricts its industrial application. How to remarkably improve the water resistance of Mn-based catalysts is a key technical problem. In this work, the H2O endurance and self-cleaning properties of OMS-2 catalysts are remarkably improved by facile process construction of hydrophobic coating. The performance of hydrophobic layer on the bulk OMS-2 catalysts surface could be effectively controlled by adjusting the PDMS (polydimethylsiloxane) vapor deposition temperature. It is discovered that the 200 oC catalyst obtained super hydrophobic property and formed with a contact angle (CA) of 160.3o, which not only exhibited satisfactory NH3-SCR activity at low temperature (140- 300 oC), but also dramatically improved H2O endurance and self-cleaning performance. Moreover, the mechanism of improving H2O resistance and stability of 200 oC catalyst was investigated in detail through a series of characterizations. Although the SCR activity of the 200 oC catalyst decreased slightly due to the combination of some active species (Oα and Mn3+) with PDMS, the H2O passivation of the active species was eliminated. The advantage of self-cleaning was confirmed by the analysis of surface species and simulation experiments, which could avoid the accumulation of intermediates on the surface and promote the stability of OMS-2 catalyst for NH3-SCR at low temperature. This process method of constructing special coating might be a huge step to remarkably improve the H2O endurance properties of catalyst and provided a new concept for future industrial application.