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Mechanism of N 2 O formation in catalytic after-treatment systems of ammonia/hydrogen-fuelled engines.
- Source :
-
Physical chemistry chemical physics : PCCP [Phys Chem Chem Phys] 2024 Jul 22. Date of Electronic Publication: 2024 Jul 22. - Publication Year :
- 2024
- Publisher :
- Ahead of Print
-
Abstract
- The combustion processes and catalytic after-treatment of ammonia/hydrogen-fueled engines, including NO <subscript> x </subscript> storage and reduction (NSR) and noble-metal selective catalytic reduction (SCR), can produce the byproduct N <subscript>2</subscript> O, a potent greenhouse gas that weakens the zero-carbon attribute of these fuels. Currently, the mechanism of N <subscript>2</subscript> O formation on DeNO <subscript> x </subscript> catalysts remains unclear due to limited research on catalytic after-treatment for such engines and the complexity of surface catalytic reactions. To elucidate the formation of N <subscript>2</subscript> O on the DeNO <subscript> x </subscript> catalysts of ammonia/hydrogen fuel engines, the impact factors on N <subscript>2</subscript> O formation on platinum catalysts (typical catalysts in NSR and noble-metal SCR) were investigated using first-principles molecular dynamics (FPMD). By employing the blue-moon ensemble enhanced sampling method and the slow-growth approach for free energy surface exploration, together with density functional theory (DFT) for electronic structure analysis, a linear relationship between the spin splitting of the d states of Pt clusters and N <subscript>2</subscript> O formation energy barriers was revealed, along with the increased structural sensitivity of Pt clusters with fewer atoms. It is highlighted that the energy barrier for N <subscript>2</subscript> O formation is determined by the matching degree of energy levels between molecules and surfaces. These findings provide atomic-scale insights into N <subscript>2</subscript> O formation on DeNO <subscript> x </subscript> catalysts for ammonia/hydrogen-fueled engines, facilitating N <subscript>2</subscript> O emission control for carbon-free engines.
Details
- Language :
- English
- ISSN :
- 1463-9084
- Database :
- MEDLINE
- Journal :
- Physical chemistry chemical physics : PCCP
- Publication Type :
- Academic Journal
- Accession number :
- 39036842
- Full Text :
- https://doi.org/10.1039/d4cp02075h