TY - JOUR

T1 - Interface interactions and CO oxidation activity of Ag/CeO2 catalysts

T2 - A new approach using model catalytic systems

AU - Kibis, Lidiya S.

AU - Svintsitskiy, Dmitry A.

AU - Kardash, Tatyana Yu

AU - Slavinskaya, Elena M.

AU - Gotovtseva, Ekaterina Yu

AU - Svetlichnyi, Valery A.

AU - Boronin, Andrei I.

N1 - Publisher Copyright: © 2018 Elsevier B.V.

PY - 2019/1/25

Y1 - 2019/1/25

N2 - In this paper, we studied in details the nature of the Ag-CeO2 interaction and its influence on the catalytic activity in CO oxidation at low temperature. Ag/CeO2 catalysts were prepared by pulsed laser ablation in liquids (PLA). This method provided the preparation of highly dispersed particles of both an active component and a support. The initial Ag/CeO2 composites did not show activity in the CO oxidation at temperatures <100 °C. However, thermal activation in an oxidizing atmosphere above 450 °C led to a significant improvement of the low-temperature catalytic characteristics and decrease of the activation energy of the reaction by 2 times. A detailed study by physicochemical methods clearly showed that the enhancement of the catalytic properties related to the transition of Ag° particles in contact with CeO2 to ionic Ag+ species. The ionic species were stabilized on the surface of CeO2 without incorporation into the ceria volume. The catalyst activated at 450 °C demonstrated high stability under catalytic conditions due to the effective reversible transition Ag+-CeO2 ↔ Agn°/CeO2, where Agn° – small metal clusters on the CeO2 surface. It is proposed that such reversible transition is facilitated by the defects on the surface of CeO2 nanoparticles. With an increase of the calcination temperature of Ag/CeO2 catalysts above 600 °C, the efficiency of the redox transition decreased due to annealing of CeO2 defects and formation of better-crystallized particles. As a result, catalysts calcined at T>600 °C did not show low-temperature catalytic activity.

AB - In this paper, we studied in details the nature of the Ag-CeO2 interaction and its influence on the catalytic activity in CO oxidation at low temperature. Ag/CeO2 catalysts were prepared by pulsed laser ablation in liquids (PLA). This method provided the preparation of highly dispersed particles of both an active component and a support. The initial Ag/CeO2 composites did not show activity in the CO oxidation at temperatures <100 °C. However, thermal activation in an oxidizing atmosphere above 450 °C led to a significant improvement of the low-temperature catalytic characteristics and decrease of the activation energy of the reaction by 2 times. A detailed study by physicochemical methods clearly showed that the enhancement of the catalytic properties related to the transition of Ag° particles in contact with CeO2 to ionic Ag+ species. The ionic species were stabilized on the surface of CeO2 without incorporation into the ceria volume. The catalyst activated at 450 °C demonstrated high stability under catalytic conditions due to the effective reversible transition Ag+-CeO2 ↔ Agn°/CeO2, where Agn° – small metal clusters on the CeO2 surface. It is proposed that such reversible transition is facilitated by the defects on the surface of CeO2 nanoparticles. With an increase of the calcination temperature of Ag/CeO2 catalysts above 600 °C, the efficiency of the redox transition decreased due to annealing of CeO2 defects and formation of better-crystallized particles. As a result, catalysts calcined at T>600 °C did not show low-temperature catalytic activity.

KW - Ag/CeO

KW - CO oxidation

KW - Interfacial interactions

KW - XPS

KW - Ag/CeO2

KW - PROBING DEFECT SITES

KW - SOOT OXIDATION

KW - METAL-SUPPORT INTERACTION

KW - ATOMICALLY DISPERSED PD

KW - LASER-ABLATED NANOPARTICLES

KW - SILVER NANOPARTICLES

KW - SPECTROSCOPIC EVIDENCE

KW - CERIA CATALYSTS

KW - IN-SITU

KW - ELECTRONIC-STRUCTURE

UR - http://www.scopus.com/inward/record.url?scp=85056468678&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/a097293d-bfbb-3ed4-bba6-7f216b18070f/

U2 - 10.1016/j.apcata.2018.11.005

DO - 10.1016/j.apcata.2018.11.005

M3 - Article

AN - SCOPUS:85056468678

VL - 570

SP - 51

EP - 61

JO - Applied Catalysis A: General

JF - Applied Catalysis A: General

SN - 0926-860X

ER -