Highly n-Type Titanium Oxide as an Electronically Active Support for Platinum in the Catalytic Oxidation of Carbon Monoxide

Type
Article

Authors
Baker, L. Robert
Hervier, Antoine
Seo, Hyungtak
Kennedy, Griffin
Komvopoulos, Kyriakos
Somorjai, Gabor A.

Online Publication Date
2011-07-27

Print Publication Date
2011-08-18

Date
2011-07-27

Abstract
The role of the oxide-metal interface in determining the activity and selectivity of chemical reactions catalyzed by metal particles on an oxide support is an important topic in science and industry. A proposed mechanism for this strong metal-support interaction is electronic activation of surface adsorbates by charge carriers. Motivated by the goal of using electronic activation to drive nonthermal chemistry, we investigated the ability of the oxide support to mediate charge transfer. We report an approximately 2-fold increase in the turnover rate of catalytic carbon monoxide oxidation on platinum nanoparticles supported on stoichiometric titanium dioxide (TiO2) when the TiO2 is made highly n-type by fluorine (F) doping. However, for nonstoichiometric titanium oxide (TiOX<2) the effect of F on the turnover rate is negligible. Studies of the titanium oxide electronic structure show that the energy of free electrons in the oxide determines the rate of reaction. These results suggest that highly n-type TiO2 electronically activates adsorbed oxygen (O) by electron spillover to form an active O- intermediate. © 2011 American Chemical Society.

Citation
Baker LR, Hervier A, Seo H, Kennedy G, Komvopoulos K, et al. (2011) Highly n-Type Titanium Oxide as an Electronically Active Support for Platinum in the Catalytic Oxidation of Carbon Monoxide. The Journal of Physical Chemistry C 115: 16006–16011. Available: http://dx.doi.org/10.1021/jp203151y.

Acknowledgements
Deposition and processing of titanium oxide films took place in the Marvell Nanolab at the University of California, Berkeley (UCB). X-ray photoelectron spectroscopy and scattering electron microscopy took place in the Molecular Foundry at Lawrence Berkeley National Lab. This work was funded by the Helios Solar Energy Research Center and by the Chemical Sciences Division, which are supported by the Director, Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and by the UCB-KAUST Academic Excellence Alliance (AEA) Program.

Publisher
American Chemical Society (ACS)

Journal
The Journal of Physical Chemistry C

DOI
10.1021/jp203151y

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