Model Studies on CO Oxidation Catalyst Systems: Titania and Gold Nanoparticles

Abstract

The peculiar catalytic activity of Au-supported titanium dioxide surfaces in the CO oxidation reaction has been a focus of interest for more than twenty years. Herein, recent data concerning preparation and structural characterisation of planar catalyst model systems consisting of single-crystalline titania and/or gold nanoparticles deposited thereon is presented and reviewed. We first expand on the deposition and growth of TiO(2) films on selected metal host surfaces and then consider the deposition of Au nanoparticles on these surfaces, including information on their geometric and electronic structures. The second issue is the interaction of these materials with carbon monoxide (one of the essential ingredients of the CO oxidation reaction) which serves as a probe molecule and monitor of the chemical activity of the model catalyst samples. Concerted efforts relating the structural and chemical properties of the respective binary materials (titania support plus deposited gold) can help to tackle and finally resolve the still open problems concerning the high activity of Au-TiO(2) catalysts in the CO oxidation reaction.

A Yolk@Shell Nanoarchitecture for Au/TiO2 Catalysts

“…Our TOF values are larger than most of those reported with conventional supported catalysts,15, 16 but slightly lower than those reported on model systems 8. 17 The latter observation can be accounted for by the relatively large size of our gold nanoparticles, which have diameters outside the optimum range reported for these applications, and which, consequently, have a lower fraction of their Au atoms directly interacting with the titania surface 8. In any case, it can be safely said that our new yolk@shell nanoarchitecture does not hinder reactivity, since the TOFs measured with the Au@TiO 2 catalyst are, if anything, larger than those with our catalyst consisting of the same gold nanoparticles ( d =10 nm) dispersed on a regular P25 titania support; a direct comparison between these two samples removes any effects caused by the Au–TiO 2 interface from the discussion.…”

Catalytic Oxidation of Carbon Monoxide over Transition Metal Oxides

“…Titania is not a popular oxide for CO oxidation even though it can be an excellent support for certain metals, especially gold 249. However, titania was recently synthesized in different crystal shapes (nanorods, nanotubes, and nanopowders) 250.…”

In-situ regeneration of Au nanocatalysts by atmospheric-pressure air plasma: Significant contribution of water vapor

“…Supported gold (Au) catalysts have been intensively investigated for catalyzing a wide variety of reactions at relatively mild conditions in the past decades [1][2][3][4][5]. Due to its superior activity on CO oxidation at low temperature [6][7][8], Au catalyst is expected as an excellent candidate for environmental protection [9][10][11][12], such as indoor air purification and canister respirators.…”