Adsorption properties of NO and NH3 over MnOx based catalyst supported on γ-Al2O3

• Adsorption of NH3/NO on the γ-Al2O3 (1 1 0) surface supported MnO2/Mn2O3 was studied.
• NO can be adsorbed stably and form different nitrite or nitrate species.
• NH3 was easily adsorbed as the coordinated NH3 on different active sites.
• Supported Mn2O3 on the surface could convert into MnO2 in the presence of O2.

Nowadays, selective catalytic reduction (SCR) of NOx with NH3 has been widely applied to reduce the emission of NOx from the power plants. MnOx based SCR catalysts have also been attracted more attention because of its several unstable valence states. But the detailed reaction mechanism is still controversial and lacks the related comparative study of molecule modeling. Since SCR reaction belongs to the gas–solid multiphase reaction, on which the adsorption of NH3 and NO on the catalysts surface would play an important role. The present study aims to probe the adsorption mechanism of NH3 and NO on the MnOx based catalysts supported on γ-Al2O3. MnO2 and Mn2O3 were supported separately on the γ-Al2O3 (1 1 0) surface, and the adsorption properties of NH3 and NO on these stable configurations were then conducted. The results shows that NO can be adsorbed stably and form different nitrite or nitrate species on the γ-Al2O3 (1 1 0) surface supported MnO2 or Mn2O3. NH3 was easily adsorbed as the coordinated NH3 on different active sites. All these calculations results are in good agreement with the experimental results. It revealed that the DFT investigation is practical in mechanism study and can provide further understandings in reaction mechanism which can hardly approach by experimental methods.