Stabilization of atomically dispersed rhodium sites on ceria-based supports under reaction conditions probed by in situ infrared spectroscopy

• Published in: Materials letters 2020-10, Vol.277, p.128354, Article 128354
• Main Authors: Vieira, Luiz H., Assaf, José M., Assaf, Elisabete M.
• Format: Article
• Language: English
• Subjects: Carbon monoxide; Ceria; Cerium oxides; Dispersion; FTIR; Infrared spectroscopy; Material properties; Materials science; Oxidation; Photoelectrons; Rhodium; Silicon dioxide; Single-site; Spectrum analysis; Surface properties; Zirconium
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2020.128354

[Display omitted] •Rhodium was deposited on pure and doped ceria surfaces.•Isolated sites were identified and quantified by CO-FTIR spectroscopy.•CeZrO2 solid solution increased by 5-fold the fraction of isolated sites.•Stabilization of single Rh sites improved activity in CO oxidation. In this work, atomically dispersed rhodium over co-precipitated ceria-based supports were prepared by wet impregnation. The structural and surface properties of materials were investigated by X-ray diffraction, N2 physisorption isotherms, and X-ray photoelectron spectroscopy. The fraction of isolated sites was quantified by infrared spectroscopy using CO as a probe molecule. The formation of a defective surface by incorporation of 15% (mol/mol) of zirconium on ceria structure increased ~5-fold the fraction of isolated sites on catalyst compared to unmodified ceria. The doped-support efficiently trapped rhodium atoms avoiding agglomeration and increasing stability during CO oxidation reaction in a wide range of temperatures (30–200 °C) when compared to single-sites deposited on silica.