Creating hierarchically macro-/mesoporous Sn/CeO2 for the selective catalytic reduction of NO with NH3

A hierarchically macro-/mesoporous Sn/CeO2 (H-Sn/CeO2) catalyst with uniform element composition and dispersion was successfully synthesized by using KIT-6 as a hard template for the selective catalytic reduction (SCR) of NO with NH3. This catalyst was mainly characterized by such techniques as transmission electron microscopy, scanning electron microscopy, X-ray diffraction, laser Raman spectroscopy, N-2 adsorption-desorption analysis, X-ray photoelectron spectroscopy, H-2 temperature-programmed reduction and NH3 temperature-programmed desorption. The obtained catalyst possesses hierarchical nanostructures with large specific surface area and good dispersion of elements. It was found that the hierarchically nanostructured Sn/CeO2 catalyst exhibited high NH3-SCR activity and a broad operating temperature window. It has been demonstrated that the Sn atoms incorporate into the crystal lattice of ceria, and more Ce3+ and O-alpha species exist on the surface of H-Sn/CeO2. It is interesting that the doping of Sn element could improve the reducibility of the H-Sn/CeO2 catalyst due to the synergetic interaction between Ce and Sn species. In addition, the H-Sn/CeO2 catalyst possesses more acidic sites and stronger acidic strength. Therefore, the obtained catalyst exhibits excellent stability and water resistance as well as enhanced SO2 tolerance.