Boosting Water-Resistance Ability on a PTFE Modified Ti-OMS-2 Catalyst for Low-Temperature NH3-SCR Reaction

Manganese-based catalysts are considered as ideal alternativecatalystsfor NH3 selective catalytic reduction of NO x due to their excellent denitrification performance,but their weak water resistance limits industrial applications. Toimprove the water resistance of low-temperature Mn-based catalystsin the NH3-SCR reaction, a Ti-OMS-2 (titanium-manganeseoxide octahedral molecular sieve) catalyst was prepared by the hydrothermalmethod, and polytetrafluoroethylene (PTFE) powder was methodicallyintroduced on the catalyst surface by the impregnation method. Importantly,the introduction of PTFE on the Ti-OMS-2 catalyst surface could effectivelyinhibit the adsorption of water molecules and reduce the probabilityof active species being consumed. Thus, it showed better catalyticactivity and water resistance. The activity of the Ti-OMS-2-20%-PTFEcatalyst could reach more than 80% when water vapor was introducedat 180 degrees C. More importantly, the Ti-OMS-2-20%-PTFE catalyst didnot readily bind the active species (Mn4+ and O-ads) and maintained the adsorption and activation of NH3 species.Moreover, it was easy for PTFE to form a weak surface hydrophobiclayer on the Ti-OMS-2 catalyst surface that could effectively inhibitwater toxicity. Therefore, this work provided a reasonable idea andexperimental accumulation for the industrial application of Mn-basedcatalysts.

Automated summary

By introducing polytetrafluoroethylene (PTFE) powder on the catalyst surface, the water resistance of Mn-based catalysts can be improved, resulting in better catalytic activity and NH3-SCR performance.