Interplay between CO Disproportionation and Oxidation: On the Origin of the CO Reaction Onset on Atomic Layer Deposition-Grown Pt/ZrO2Model Catalysts
Journal article, 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

operando

DFT

SFG

in situ spectroscopy

catalysis

NAP-XPS

Author

Verena Pramhaas

Vienna University of Technology

Matteo Roiaz

Vienna University of Technology

Noemi Bosio

Chalmers, Physics, Chemical Physics

Manuel Corva

Laboratorio Nazionale TASC

University of Trieste

Christoph Rameshan

Vienna University of Technology

Erik Vesselli

Laboratorio Nazionale TASC

University of Trieste

Henrik Grönbeck

Chalmers, Physics, Chemical Physics

G. Rupprechter

Vienna University of Technology

ACS Catalysis

2155-5435 (eISSN)

Vol. 11 1 208-214

Catalytic activity from first principles

Swedish Research Council (VR), 2017-01-01 -- 2020-12-31.

Subject Categories

Inorganic Chemistry

Materials Chemistry

Other Chemistry Topics

DOI

10.1021/acscatal.0c03974

PubMed

33425478

More information

Latest update

1/20/2021