TY - JOUR

T1 - Redox and Catalytic Properties of RhxCe1-xO2-δ Solid Solution

AU - Kibis, Lidiya S.

AU - Kardash, Tatyana Yu

AU - Derevyannikova, Elizaveta A.

AU - Stonkus, Olga A.

AU - Slavinskaya, Elena M.

AU - Svetlichnyi, Valery A.

AU - Boronin, Andrei I.

PY - 2017/12/7

Y1 - 2017/12/7

N2 - In this work, a detailed study of the redox properties of solid solution RhxCe1-xO2-δ in correlation with its catalytic activity in CO oxidation reaction was carried out. The ex situ X-ray photoelectron spectroscopy technique was applied to follow the charging states of the elements on the surface during the redox treatments at a temperature range of 25-450 °C. The results were compared with the data of temperature-programmed reduction by CO. The dissolution of rhodium in the ceria bulk considerably increased the mobility of CeO2 lattice oxygen, with redox transitions Ce4+ ↔ Ce3+ and Rh3+ ↔ Rhn δ+ observed already at low temperatures (below 150 °C). The reduced rhodium clusters (Rhn δ+) formed during the reduction treatment significantly improved the catalytic activity of the RhxCe1-xO2-δ solid solution. The small size of the rhodium clusters (Rhn δ+) and high defectiveness of the fluorite phase provided the reversibility of Rhn δ+/CeO2 ↔ RhxCe1-xO2-δ transitions upon redox treatment, resulting in the high reproducibility of the CO conversion curves in the temperature-programmed reaction CO + O2. The homogeneous solid solution was stable up to 800 °C. Above this temperature, the CeO2 volume was depleted of Rh3+ ions because of their partial segregation into the surface and/or subsurface layers with the formation of Rh2O3. For these inhomogeneous samples, the oxygen mobility was considerably lower, while the redox transitions, Ce4+ ↔ Ce3+ and Rh3+ ↔ Rhn δ+, required higher temperatures.

AB - In this work, a detailed study of the redox properties of solid solution RhxCe1-xO2-δ in correlation with its catalytic activity in CO oxidation reaction was carried out. The ex situ X-ray photoelectron spectroscopy technique was applied to follow the charging states of the elements on the surface during the redox treatments at a temperature range of 25-450 °C. The results were compared with the data of temperature-programmed reduction by CO. The dissolution of rhodium in the ceria bulk considerably increased the mobility of CeO2 lattice oxygen, with redox transitions Ce4+ ↔ Ce3+ and Rh3+ ↔ Rhn δ+ observed already at low temperatures (below 150 °C). The reduced rhodium clusters (Rhn δ+) formed during the reduction treatment significantly improved the catalytic activity of the RhxCe1-xO2-δ solid solution. The small size of the rhodium clusters (Rhn δ+) and high defectiveness of the fluorite phase provided the reversibility of Rhn δ+/CeO2 ↔ RhxCe1-xO2-δ transitions upon redox treatment, resulting in the high reproducibility of the CO conversion curves in the temperature-programmed reaction CO + O2. The homogeneous solid solution was stable up to 800 °C. Above this temperature, the CeO2 volume was depleted of Rh3+ ions because of their partial segregation into the surface and/or subsurface layers with the formation of Rh2O3. For these inhomogeneous samples, the oxygen mobility was considerably lower, while the redox transitions, Ce4+ ↔ Ce3+ and Rh3+ ↔ Rhn δ+, required higher temperatures.

KW - METAL-SUPPORT INTERACTION

KW - TEMPERATURE CO OXIDATION

KW - ION-SUBSTITUTED CEO2

KW - NOBLE-METAL

KW - PLATINUM NANOPARTICLES

KW - ELECTRONIC INTERACTION

KW - PEROVSKITE CATALYST

KW - RAMAN-SPECTROSCOPY

KW - THERMAL-STABILITY

KW - OXIDE-FILM

UR - http://www.scopus.com/inward/record.url?scp=85038209237&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.7b09983

DO - 10.1021/acs.jpcc.7b09983

M3 - Article

AN - SCOPUS:85038209237

VL - 121

SP - 26925

EP - 26938

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 48

ER -