Interplay between the metal- support interaction and stability in Pt/ Co3O4(111) model catalysts

Lykhach Y, Faisal F, Skala T, Neitzel A, Tsud N, Vorokhta M, Dvorak F, Beranova K, Kosto Y, Prince KC, Matolin V, Libuda J (2018)

Publication Status: Published

Publication Type: Journal article

Publication year: 2018

Journal

Journal of Materials Chemistry A Royal Society of Chemistry

Publisher: ROYAL SOC CHEMISTRY

Book Volume: 6

Pages Range: 23078-23086

Journal Issue: 45

DOI: 10.1039/c8ta08142e

Abstract

The interplay between the metal-support interaction and stability with respect to sintering has been investigated for Pt nanoparticles supported on well-ordered Co3O4(111)/Ir(100) films in UHV and under oxidizing conditions by means of synchrotron radiation photoelectron spectroscopy (SRPES) and near ambient pressure X-ray photoelectron spectroscopy (NAP XPS). The electronic metal-support interaction between Pt and Co3O4(111) associated with charge transfer results in partial reduction of Co3O4(111) yielding partially oxidized Pt+ species at the interface. The stability of the supported Pt particles is coupled with the oxidation state of Pt+ species, which can be reduced or oxidized depending on the Pt coverage and reactive environment. Annealing of Pt/Co3O4(111)/Ir(100) in UHV triggers the reduction of Pt+ species. At higher temperature, reverse spillover of oxygen to the Pt nanoparticles is accompanied by reduction of Co3O4(111). Under these conditions, the oxidation state of Pt+ species depends strongly on Pt coverage. Thus, at low Pt coverage (0.3 ML Pt), Pt+ is converted to Pt4+, at intermediate coverage (1.3 ML Pt), Pt+ remains stable, and at high Pt coverage (1.93 ML), Pt+ is reduced to Pt-0. Sintering of Pt particles is associated with the reduction of the Pt+ species. This process is prevented under oxidizing conditions due to the formation of an interfacial oxide PtOx. The formation of an interfacial PtOx is observed at 300 K under exposure to 1 x 10(-6) mbar O-2 at Pt coverages below 1.3 ML. Using NAP XPS, we observe the formation of an interfacial PtOx at high Pt coverage (2.0 ML) in an oxygen atmosphere (1 mbar) at 300 K while the formation of surface PtOx is kinetically hindered and occurs above 550 K only.

Authors with CRIS profile

Yaroslava Lykhach Lehrstuhl für Physikalische Chemie II Firas Faisal Lehrstuhl für Physikalische Chemie II Armin Neitzel Lehrstuhl für Physikalische Chemie II Jörg Libuda Professur für Physikalische Chemie

Additional Organisation(s)

Exzellenz-Cluster Engineering of Advanced Materials (EAM)

Involved external institutions

Univerzita Karlova v Praze / Charles University in Prague CZ Czech Republic (CZ) Elettra Sincrotrone Trieste S.C.p.A. IT Italy (IT)

How to cite

APA:

Lykhach, Y., Faisal, F., Skala, T., Neitzel, A., Tsud, N., Vorokhta, M.,... Libuda, J. (2018). Interplay between the metal- support interaction and stability in Pt/ Co3O4(111) model catalysts. Journal of Materials Chemistry A, 6(45), 23078-23086. https://doi.org/10.1039/c8ta08142e

MLA:

Lykhach, Yaroslava, et al. "Interplay between the metal- support interaction and stability in Pt/ Co3O4(111) model catalysts." Journal of Materials Chemistry A 6.45 (2018): 23078-23086.

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