Adsorption properties of NO, NH3, and O2 over β-MnO2(110) surface

Selective catalytic reduction (SCR) of NO x with NH3 has been widely adopted to reduce NO x emissions. Although MnO x -based catalysts exhibit higher NO x conversion, the underlying reaction mechanism is still unclear. Since the SCR is a gas–solid catalytic reaction, the adsorption of related gas species on the catalyst surface plays a key role. In this study, the adsorption of NO, NH3, and O2 on β-MnO2(110) surface was investigated by density functional theory calculations, showing their individual adsorption properties. Two different gas molecules can also simultaneously adsorb on the same adsorption site. When NO and O2 co-adsorb on the surface, NO is oxidized by O2 to form bridge nitrates and nitrites. This work provides a foundation for studying the mechanism of the SCR of NO x with NH3.