A γ-Fe2O3-modified nanoflower-MnO2/attapulgite catalyst for low temperature SCR of NOx with NH3

Abstract

A mesoporous γ-Fe₂O₃-modified nanoflower-MnO₂/attapulgite (γ-Fe₂O₃/nf-MnO₂–ATP) catalyst was fabricated through a facile hydrothermal method. The results of TEM and XRD indicated that γ-Fe₂O₃/nf-MnO₂–ATP presented a beautiful nanoflower shape and good dispersion. The BET results showed that the specific surface area and pore volume of γ-Fe₂O₃/nf-MnO₂–ATP significantly increased after surface modification with γ-Fe₂O₃. Also, the XPS and NH₃-TPD results illustrated that the γ-Fe₂O₃ coating could enhance the amounts of surface chemisorbed oxygen and acidic sites. SO₂ and H₂O tolerance tests and stability tests demonstrated that γ-Fe₂O₃/nf-MnO₂–ATP can effectively inhibit SO₂ and H₂O poisoning and improve the stability of the catalyst. The superior SCR performance can be attributed to the abundant acid sites, the strong adsorption of NO_x, and the formation of more oxygen vacancies as well as metal–metal interactions. Therefore, γ-Fe₂O₃/nf-MnO₂–ATP was proved to be an excellent catalyst for NH₃-SCR and may be of interest in other environmental catalysis applications.