Alkali metal poisoning has been a complex yet unresolved issue restricting the catalytic activity of NH3–SCR catalysts in industry to date. Herein, the effect of K deposition on the catalytic activity of Fe/beta catalysts for NH3–SCR of NO x was systematically investigated by a series of experimental characterizations and density functional theory (DFT) calculations. It has been determined that a lower K deposition could activate and facilitate the transfer of electrons and enhance the ratio of Fe2+/Fe3+ and reducible Fe species, thereafter promoting the NO and O2 adsorption and decreasing the activation energy of NO to NO2, and thereby significantly improving the catalytic activity of 0.25% K–Fe/Beta. To the best of our knowledge, this phenomenon has not been reported in the field of exhaust abatement. Nevertheless, excessive K deposition (≥0.50%) can not only occupy the Brönsted acid sites, leading to perceptible aggregation of the active Fe species and an increase in the activation energy for NO oxidation on Lewis acid sites, but also induce the generation of inactive nitrates, blocking the pore structure of the Beta molecular sieve, resulting in the distinctive reduction of catalytic active Fe species, thereby seriously restricting the catalytic performances of 0.50% K–Fe/beta and 1.0% K–Fe/beta catalysts. Thus, this study may shine light on the deep understanding of alkali metal poison during NH3–SCR of NO x and the design of advanced catalysts in heterogeneous catalysis in the future.

Porous CeWOx catalysts with impressive specific surface areas and deNOx activity were constructed by a rapid and solvent-free strategy.

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A novel superhydrophobic coating composed of soft polydimethylsiloxane microspheres and stiff SiO 2 nanoparticles was developed and prepared. This superhydrophobic coating showed excellent superhydrophobicity with a large water contact angle of 171.3°and also exhibited good anti-icing performance and ultralow icing adhesion of 1.53 kPa. Furthermore, the superhydrophobic coating displayed good icing/deicing cycle stability, in which the icing adhesion was still less than 10.0 kPa after 25 cycles. This excellent comprehensive performance is attributed to stress-localization between ice and the surface, resulting from the synergistic effect of soft and stiff particles. This work thus opens a new avenue to simultaneously optimize the antiicing and icephobic performance of a superhydrophobic surface for various applications.

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