Origin of Ammonia Selective Oxidation Activity of SmMnO Mullite: A First-Principles-Based Microkinetic Study.

Based on first-principles calculations and microkinetic analysis, the reaction routes and origin of the activity of SmMnO mullite for the selective catalytic oxidation of ammonia (NH-SCO) are systematically investigated on three low-index surfaces under experimentally operating conditions. Key influencing factors and contributions of different iconic intermediate species (NH*, NH*, and HNO*) to the overall reaction process have been identified. In detail, Mn serves as the primary active site for NH adsorption, while lattice oxygen participates in the dehydrogenation of NH on (010) and (001) surfaces.