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Design of thin-film nanocatalysts for on-chip fuel cell technology

Nature Materials article

Counting electrons on supported nanoparticles

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Nature Materials online published on line on December 14, 2015 read more on Nature Publishing pages

Yaroslava Lykhach1, Sergey M. Kozlov2 Tomáš Skála3, Andrii Tovt3, Vitaliy Stetsovych3, Nataliya Tsud3, Filip Dvořák3, Viktor Johánek3, Armin Neitzel1, Josef Mysliveček3, Stefano Fabris4, Vladimír Matolín3, Konstantin M. Neyman2,5,*, Jörg Libuda1,6,*,

1 Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg (Germany)
2 Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona c/Martí i Franquès 1, 08028 Barcelona (Spain)
3Department of Surface and Plasma Science, Charles University, V Holešovičkách 2, 18000 Prague (Czech Republic)
4 CNR-ION DEMOCRITOS, Instituto Officina dei Materiali, Consiglio Nazionale delle Ricerche and SISSA, Via Bonomea 265, I-34136 Trieste (Italy)
5 Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010 Barcelona (Spain)
6 Erlangen Catalysis Resource Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen (Germany)

Electronic interactions between metal nanoparticles and oxide supports control the functionality of nanomaterials, for example, the stability, the activity and the selectivity of catalysts[1-5]. Such interactions involve electron transfer across the metal/support interface. In this work we quantify this charge transfer on a well-defined platinum/ceria catalyst at particle sizes relevant for heterogeneous catalysis. Combining synchrotron-radiation photoelectron spectroscopy, scanning tunnelling microscopy and density functional calculations we show that the charge transfer per Pt atom is largest for Pt particles of around 50 atoms. Here, approximately one electron is transferred per ten Pt atoms from the nanoparticle to the support. For larger particles, the charge transfer reaches its intrinsic limit set by the support. For smaller particles, charge transfer is partially suppressed by nucleation at defects. These mechanistic and quantitative insights into charge transfer will help to make better use of particle size effects and electronic metal–support interactions in metal/oxide nanomaterials.