Application of atomic-scale mechanistic insights into carbon-catalyzed N₂O reduction for kinetic modeling...

To achieve the collaborative elimination of N₂O and carbon of potent greenhouse pollutants from automotive mobile sources, a chemical kinetic model is developed to accurately track the heterogeneous process of carbon-catalyzed N₂O reduction based on density functional theory, with experimental data used to validate the model's reliability. The influence of carbon structure, site density, and surface chemical properties on N₂O catalytic reduction can be analyzed within this system. Results reveal that the free-edge site of carbon accurately describes the catalytic reduction process of N₂O. Adsorption of N₂O to carbon edges in O-down, N-down, or parallel orientations exhibits an exothermic process with energy barriers. The N₂O with O-down reduction pathway predominates due to the limitations imposed by the unitary carbon site. As the number of active carbon atoms at carbon edges increases, the N₂O reaction mode tends towards parallel and N-down pathways, resulting in a significant enhancement of N₂O conversion rates and a reduction in catalytic temperatures, with the lowest achievable temperature being 300 K. Furthermore, the triplet carbon structure exhibits higher efficiency in N₂O catalytic reduction compared to the singlet carbon structure, achieving a remarkable N₂O conversion rate of 93.8 % within the typical temperature exhaust window of diesel engines. This study supplies a breakthrough for carbon materials as catalysts for achieving high N₂O conversion rates at low cost, which is important for the collaborative catalytic elimination of N₂O and carbon black pollutants.