Selective catalytic reduction of NO over W-Zr-Ox/TiO2: performance study of hierarchical pore structure

A series of W-Zr-O-x/TiO2 catalysts with hierarchical pore structure were prepared and used for selective catalytic reduction of NO by NH3. Results showed that the 5C-WZ/T had a hierarchical pore structure, and exhibited high catalytic activity and good resistance to water and sulfur poisoning. The activity of the 5C-WZ/T catalyst was close to 100% in the range of 350-500 degrees C. The hierarchical pore structure not only improved the specific surface area, redox performance, and acid quantity, but also enabled the catalyst to expose more active sites and improved the catalytic performance. Although the reducing atmosphere caused by citric acid monohydrate reduced the chemical adsorption oxygen concentration, it increased the oxygen mobility and Ti3+ ion concentration, which was more conducive to the improvement of catalytic activity. Finally, the NH3-SCR reaction over 5C-WZ/T catalyst followed L-H and E-R mechanisms. The monodentate nitrite, bidentate nitrate, gas-phase NO2, coordinated NH3 and NH4+ were the main reaction intermediates.

Automated summary

The W-Zr-O-x/TiO2 catalysts with hierarchical pore structure, especially the 5C-WZ/T, showed high catalytic activity and resistance to water and sulfur poisoning. The hierarchical pore structure improved specific surface area, redox performance, and acid quantity, leading to exposure of more active sites and enhanced catalytic performance. The NH3-SCR reaction over 5C-WZ/T catalyst followed L-H and E-R mechanisms involving various reaction intermediates.