Article abstract
Nature Materials 7, 333 - 338 (2008)
Published online: 16 March 2008 | doi:10.1038/nmat2156
Subject Categories: Catalytic materials | Materials for energy | Nanoscale materials
Ru–Pt core–shell nanoparticles for preferential oxidation of carbon monoxide in hydrogen
Selim Alayoglu1, Anand U. Nilekar2, Manos Mavrikakis2 & Bryan Eichhorn1
Abstract
Most of the world's hydrogen supply is currently obtained by reforming hydrocarbons. 'Reformate' hydrogen contains significant quantities of CO that poison current hydrogen fuel-cell devices. Catalysts are needed to remove CO from hydrogen through selective oxidation. Here, we report first-principles-guided synthesis of a nanoparticle catalyst comprising a Ru core covered with an approximately 1–2-monolayer-thick shell of Pt atoms. The distinct catalytic properties of these well-characterized core–shell nanoparticles were demonstrated for preferential CO oxidation in hydrogen feeds and subsequent hydrogen light-off. For H2 streams containing 1,000 p.p.m. CO, H2 light-off is complete by 30 °C, which is significantly better than for traditional PtRu nano-alloys (85 °C), monometallic mixtures of nanoparticles (93 °C) and pure Pt particles (170 °C). Density functional theory studies suggest that the enhanced catalytic activity for the core–shell nanoparticle originates from a combination of an increased availability of CO-free Pt surface sites on the Ru@Pt nanoparticles and a hydrogen-mediated low-temperature CO oxidation process that is clearly distinct from the traditional bifunctional CO oxidation mechanism.
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
Correspondence to: Manos Mavrikakis2 e-mail: manos@engr.wisc.edu
Correspondence to: Bryan Eichhorn1 e-mail: eichhorn@umd.edu
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