Structural and Catalytic Properties of Rh–CeO2/MWCNT Composite Catalysts

• Published in: Journal of structural chemistry Vol. 65; no. 3; pp. 504 - 516
• Main Authors: Kibis, L. S., Zadesenets, A. V., Kardash, T. Yu, Korenev, S. V., Stonkus, O. A., Slavinskaya, E. M., Podyacheva, O. Yu, Boronin, A. I.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.03.2024; Springer Nature B.V
• Subjects: Atomic; Atomic/Molecular Structure and Spectra; Carbon monoxide; Catalysts; Catalytic activity; Cerium oxides; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Molecular; Multi wall carbon nanotubes; Optical and Plasma Physics; Oxidation; Photoelectrons; Physical Chemistry; Rhodium; Solid State Physics; Transmission electron microscopy; X ray photoelectron spectroscopy; Rh/CeO; MWCNTs; nanoparticles; composite catalyst; clusters; low-temperature CO oxidation
• ISSN: 0022-4766; 1573-8779
• DOI: 10.1134/S0022476624030077

Composite catalysts consisting of Rh–CeO x structures supported on the surface of multi-walled carbon nanotubes (MWCNTs) are studied. For supported active components (Rh, Ce) the rhodium content is maintained constant on the MWCNT surface and the cerium concentration is varied in the range Rh at /Ce at  = 0.085-0.34. The obtained samples are investigated by a combination of structural (X-ray diffraction, transmission electron microscopy (TEM)), spectral (X-ray photoelectron spectroscopy (XPS)), and kinetic (temperature-programmed reaction with CO (TPR-CO) and CO+O 2 (TPR-CO+O 2 )) techniques. Highly dispersed CeO 2 and RhO x particles are found to form in all samples studied. When the Rh at /Ce at ratio is changed, structures are formed that exhibit the catalytic activity in the CO oxidation reaction for different temperature ranges. At low Rh at /Ce at ratios (< 0.17) the CO conversion is observed at temperatures above 100 °C. When the Rh at /Ce at ratio increases, centers exhibiting the catalytic activity at temperatures below 0 °C are formed in Rh–CeO 2 /MWCNT catalysts. HR-TEM and TPR-CO studies of composite catalysts with a high Rh at /Ce at ratio reveal that structures based on dispersed oxidized rhodium particles modified by Ce 3+ ions can be active species.