Structure–activity relationship of Au/ZrO₂ catalyst on formation of hydroxyl groups and its influence on CO oxidation

Journal Article · Tue Mar 26 00:00:00 EDT 2013 · Journal of Materials Chemistry. A

DOI:https://doi.org/10.1039/c3ta00081h· OSTI ID:1080265

Karwacki, Christopher J. ^[1]; Ganesh, P. ^[2]; Kent, Paul R. C. ^[3]; Gordon, Wesley O. ^[1]; Peterson, Gregory W. ^[1]; Niu, Jun Jie ^[4]; Gogotsi, Yury ^[4]

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1. Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Science and Mathematics Division
4. Drexel Univ., Philadelphia, PA (United States). A. J. Drexel Nanotechnology Inst., Dept. of Materials Science and Engineering

We studied the effect of changes in morphology and surface hydroxyl species upon thermal treatment of zirconia on the oxidation activity of Au/ZrO₂ catalyst. We observed using transmission Fourier transform infrared (FTIR) spectroscopy progressive changes in the presence of monodentate (type I), bidentate (type II) and hydrogen bridged species (type III) for each of the thermally treated (85 to 500 C) supports consisting of bare zirconia and Au/ZrO₂ catalysts. Furthermore, structural changes in zirconia were accompanied by an increase in crystal size (7 to 58 nm) and contraction of the supports porosity (SSA 532 to 7 m² g^-1) with increasing thermal treatment. Deposition of gold nanoparticles under similar preparation conditions on different thermally treated zirconia resulted in changes in the mean gold cluster size, ranging from 3.7 to 5.6 nm. Changes in the surface hydroxyl species, support structure and size of the gold centers are important parameters responsible for the observed decrease (>90%) in CO conversion activity for the Au/ZrO₂ catalysts. Density functional theory calculations provide evidence of increased CO binding to Au nanoclusters in the presence of surface hydroxyls on zirconia, which increases charge transfer at the perimeter of the gold nanocluster on zirconia support. This further helps in reducing a model CO-oxidation reaction barrier in the presence of surface hydroxyls. In conclusion, this work demonstrates the need to understand the structure activity relationship of both the support and active particles for the design of catalytic materials.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1080265
• Journal Information: Journal of Materials Chemistry. A, Vol. 1, Issue 19; ISSN 2050-7488
• Publisher: Royal Society of Chemistry
• Country of Publication: United States
• Language: English

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY