Interplay between CO Disproportionation and Oxidation: On the Origin of the CO Reaction Onset on Atomic Layer Deposition-Grown Pt/ZrO2Model Catalysts
Artikel i vetenskaplig tidskrift, 2021

Pt/ZrO2 model catalysts were prepared by atomic layer deposition (ALD) and examined at mbar pressure by operando sum frequency generation (SFG) spectroscopy and near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) combined with differentially pumped mass spectrometry (MS). ALD enables creating model systems ranging from Pt nanoparticles to bulk-like thin films. Polarization-dependent SFG of CO adsorption reveals both the adsorption configuration and the Pt particle morphology. By combining experimental data with ab initio density functional theory (DFT) calculations, we show that the CO reaction onset is determined by a delicate balance between CO disproportionation (Boudouard reaction) and oxidation. CO disproportionation occurs on low-coordinated Pt sites, but only at high CO coverages and when the remaining C atom is stabilized by a favorable coordination. Thus, under the current conditions, initial CO oxidation is found to be strongly influenced by the removal of carbon deposits formed through disproportionation mechanisms rather than being determined by the CO and oxygen inherent activity. Accordingly, at variance with the general expectation, rough Pt nanoparticles are seemingly less active than smoother Pt films. The applied approach enables bridging both the "materials and pressure gaps".

Pt nanoparticles




in situ spectroscopy




Verena Pramhaas

Technische Universität Wien

Matteo Roiaz

Technische Universität Wien

Noemi Bosio

Chalmers, Fysik, Kemisk fysik

Manuel Corva

Laboratorio Nazionale TASC

Universita degli Studi di Trieste

Christoph Rameshan

Technische Universität Wien

Erik Vesselli

Laboratorio Nazionale TASC

Universita degli Studi di Trieste

Henrik Grönbeck

Chalmers, Fysik, Kemisk fysik

G. Rupprechter

Technische Universität Wien

ACS Catalysis

21555435 (eISSN)

Vol. 11 1 208-214

Länk mellan katalytisk aktivitet och kvantmekaniska beräkningar

Vetenskapsrådet (VR) (2016-05234), 2017-01-01 -- 2020-12-31.


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