Observation and Characterization of Dicarbonyls on a RhCu Single-Atom Alloy

• Published in: The journal of physical chemistry letters 2022-07, Vol.13 (27), p.6316-6322
• Main Authors: Wang, Yicheng, Schumann, Julia, Happel, Elizabeth E., Çınar, Volkan, Sykes, E. Charles H., Stamatakis, Michail, Michaelides, Angelos, Hannagan, Ryan T.
• Format: Article
• Language: English
• Subjects: Chemistry; Materials Science; Physical Insights into Chemistry, Catalysis, and Interfaces; Physics; Science & Technology - Other Topics
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.2c01596

Dicarbonyl species are ubiquitous on Rh/oxide catalysts and are known to form on Rh+ centers. However, dicarbonyl species have never been directly observed on single-atom alloys (SAAs) where the active site is metallic. Herein, using surface science and theoretical modeling, we provide evidence of dicarbonyl species at isolated Rh sites on a RhCu(100) SAA. This approach not only enables us to directly visualize dicarbonyl species at Rh sites but also demonstrates that the transition between the mono- and dicarbonyl configuration can be achieved by changing surface temperature and CO pressure. Density functional theory calculations further support the mono- and dicarbonyl assignments and provide evidence that these species should be stable on other SAA combinations. Together, these results provide a picture of the structure and energetics of both the mono- and dicarbonyl configurations on the RhCu(100) SAA surface and should aid with IR assignments on SAA nanoparticle catalysts.