2021 Fiscal Year Annual Research Report
Elucidation and Design of NO Reduction Reaction Process by First-Principles Multiscale Simulation
| Project/Area Number |
21J10648
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| Research Institution | Osaka University |
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Principal Investigator |
PHAM THANH NGOC 大阪大学, 工学研究科, 特別研究員(DC2)
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| Project Period (FY) |
2021-04-28 – 2023-03-31
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| Keywords | three-way catalyst / NO reduction reaction |
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| Outline of Annual Research Achievements |
We studied the co-adsorption of NO-H2O on Cu(111) using the van der Waals density functional theory method. We first studied the adsorption of NO and H2O clusters on Cu(111). The energetics, adsorption geometries, and vibrational properties of several NO-H2O complexes are estimated, and the relative stabilities of those complexes are compared with respective NO and H2O clusters on Cu(111). We find that the mixed complexes between NO and H2O on Cu(111) are more stable than the separated clusters of NO and water, which arises from the hydrogen bonding between NO and H2O and NO - NO interaction. Electronic structure analysis indicates that attractive NO-H2O interaction arises from the hydrogen bonding with the enhancements of back-donation to valence orbitals of NO, while the NO - NO interaction arises from the hybridization among valance orbitals. The vibrational analysis also confirms the formation of the mixed NO-H2O complexes and N-O stretching modes are red-shifted due to hydrogen bonding with water. Our result provides an insightful interpretation of experimental observation.
We also have studied the metal-support interaction (MSI) of the platinum metal group (PGM) supported on some metal oxide materials under three-way catalyst (TWC) operating conditions using machine-learning enhanced global optimization and thermodynamics.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
The purpose of this research is to elucidate and design nitric oxide (NO) reduction reaction (NORR) process in the three-way catalyst (TWC) by first-principles multiscale simulation.
(1) We studied the co-adsorption of NO-H2O on Cu(111) and provided the origin of pellicular behavior of NO and H2O on Cu(111). The result is important for the use of the Cu catalyst in TWC.
(2) We also revealed the precise structure and stability of the platinum metal group (PGM) NPs supported on some metal oxide materials under three-way catalyst (TWC) operating conditions. The role of working conditions in the thermal stability of the supported NPs is evaluating now. Further clarification of this will provide guidelines for designing more desirable catalysts
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| Strategy for Future Research Activity |
We aim to (i) study precise structures of PGM NPs supported on perovskite under catalyst operating conditions and (ii) evaluate the dynamics of the sintering process at high temperatures. The precise structure of the supported PGM NPs under real aging (with the presence of oxygen and water) and working conditions shall be studied using density functional theory combined with machine learning enhanced global optimization (GOFEE) and thermodynamics. We then shall study the dynamics of the sintering process of PGM NPs at high temperatures using multiscaled quantum simulation. We plan to use Monte Carlo or molecular dynamics simulations to evaluate the growth of larger NPs from smaller ones by the Otsward ripening mechanism and reveal the effect of metal-support interaction on sintering resistance.
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