Highly active alkali etching silica-modified Cu-Ce-Ti catalyst with superior water resistance for low temperature NOx reduction

In this study, Cu-Ce oxides supported on a silica modified TiO2 with post-alkali treatment (Cu-Ce/TS-am) were synthesized to enhance the catalytic activity and water resistance for low-temperature NOx reduction with ammonia. Experiment results revealed that the optimal Cu-Ce/TS-am sample possessed over 90% NOx conver-sion at 180-350 degrees C in the presence of 10 vol% water. Essentially, the formed Ti-Si strong interactions after Si addition could be responsible for that. On the one hand, the interactions increased specific surface area, total acidity and oxygen mobility, thus promoting SCR activity. On the other hand, it could enhance the hydropho-bicity of the catalysts as there existed lower surface roughness, smaller particle size and enlarged mesoporous pore size after Si addition, alleviating the competitive adsorption of water with NH3. Additionally, the alkali treatment removed uncombined SiOx, which optimized the mesoporous pore structure and increased the exposure of active sites and acidic sites on the catalyst surface, further enhancing water resistance and catalytic activity. These findings could provide useful guidelines for the development of highly active SCR catalyst with well water resistance in real application.

Automated summary

In this study, Cu-Ce/TS-am catalysts were synthesized to enhance the catalytic activity and water resistance for low-temperature NOx reduction with ammonia. The optimized Cu-Ce/TS-am sample achieved over 90% NOx conversion at 180-350 degrees C in the presence of water. The addition of Si improved specific surface area, total acidity, and oxygen mobility, promoting SCR activity. Moreover, alkali treatment optimized the mesoporous pore structure and increased the exposure of active sites and acidic sites, further enhancing water resistance and catalytic activity. These findings provide useful guidelines for developing highly active and water-resistant SCR catalysts in real applications.