Metallic corner atoms in gold clusters supported on rutile are the dominant active site during water-gas shift catalysis

W Damion Williams; Mayank Shekhar; Wen-Sheng Lee; Vincent Kispersky; W Nicholas Delgass; Fabio H Ribeiro; Seung Min Kim; Eric A Stach; Jeffrey T Miller; Lawrence F Allard

doi:10.1021/ja1064262

Metallic corner atoms in gold clusters supported on rutile are the dominant active site during water-gas shift catalysis

J Am Chem Soc. 2010 Oct 13;132(40):14018-20. doi: 10.1021/ja1064262.

Authors

W Damion Williams¹, Mayank Shekhar, Wen-Sheng Lee, Vincent Kispersky, W Nicholas Delgass, Fabio H Ribeiro, Seung Min Kim, Eric A Stach, Jeffrey T Miller, Lawrence F Allard

Affiliation

¹ School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA.

PMID: 20853899
DOI: 10.1021/ja1064262

Abstract

Au/TiO(2) catalysts used in the water-gas shift (WGS) reaction at 120 °C, 7% CO, 22% H(2)O, 9% CO(2), and 37% H(2) had rates up to 0.1 moles of CO converted per mole of Au per second. However, the rate per mole of Au depends strongly on the Au particle size. The use of a nonporous, model support allowed for imaging of the active catalyst and a precise determination of the gold size distribution using transmission electron microscopy (TEM) because all the gold is exposed on the surface. A physical model of Au/TiO(2) is used to show that corner atoms with fewer than seven neighboring gold atoms are the dominant active sites. The number of corner sites does not vary as particle size increases above 1 nm, giving the surprising result that the rate per gold cluster is independent of size.