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A flat-lying dimer as a key intermediate in NO reduction on Cu(100).
Kenta Kuroishi1, Muhammad Rifqi Al Fauzan, Thanh Ngoc Pham
1Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan. hokuyama@kuchem.kyoto-u.ac.jp.
Physical Chemistry Chemical Physics : PCCP
|July 30, 2021
Summary
Nitric oxide (NO) dissociates at a low temperature on copper (Cu)(100) surfaces. This high reactivity is attributed to the formation of (NO)2 and flat-lying ONNO intermediates, facilitating dissociation.
Area of Science:
- Surface science
- Chemical kinetics
- Materials science
Background:
- Nitric oxide (NO) interactions with metal surfaces are crucial for catalysis and materials science.
- Copper surfaces (Cu) are widely used catalysts, and understanding NO reactions is essential.
Purpose of the Study:
- To investigate the reaction mechanism and kinetics of nitric oxide (NO) adsorption and dissociation on the Cu(100) surface.
- To compare the reactivity of NO on Cu(100) with other copper surfaces (Cu(111) and Cu(110)).
Main Methods:
- Scanning tunneling microscopy (STM) for atomic-level surface imaging.
- Electron energy loss spectroscopy (EELS) for vibrational analysis of adsorbed species.
- Density functional theory (DFT) calculations for theoretical modeling of reaction pathways and energies.
Main Results:
- NO molecules adsorb as monomers at 64 K and dissociate into oxygen atoms around 70 K on Cu(100).
- The dissociation temperature on Cu(100) is significantly lower than on Cu(111) and Cu(110).
- The reaction proceeds via (NO)2 dimer formation, followed by a flat-lying ONNO intermediate, which then dissociates with low activation energy.
Conclusions:
- The formation of (NO)2 and the flat-lying ONNO intermediate are key factors enabling the exceptionally high reactivity of NO on the Cu(100) surface.
- This study provides fundamental insights into the surface chemistry of NO on copper, relevant for catalytic applications.
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