11. February 2016
Eeny, meeny, miny, moe ... Counting with catalyst nanoparticles
Researchers have investigated how much electrical charge nanoparticles transfer to their support for the first time. Image: Sergey Kozlov and Oriol Lamiel
No matter whether we look at catalytic processes in chemical industry, at environmental catalysis or at new devices for energy storage and transformation, metallic nanoparticles are omnipresent in new and emerging technologies. Their special chemical and physical properties are at the heart of modern methods and devices that help to make more efficient use of our materials and energy resources. Often the special properties of nanoparticles are not intrinsic but they arise from a chemical interaction with their surroundings, for example with the support material that they are placed on. Such interactions often change the electronic structure of the nanoparticle, for instance because electrical charge is exchanged between the particle and the support. Reporting in Nature Materials, the research groups of Prof. J. Libuda (EAM/FAU) and Prof. K. Neyman (Barcelona) and their cooperation partners reveal how the number of elementary charges lost by a platinum nanoparticle when it is placed onto an oxide support can be counted. The magnitude of the effect is surprisingly large: Approximately every tenth metal atom loses an electron when the particle comes in contact with the oxide.
To measure the electrical charge exchanged between the catalyst particle and its surrounding the international team of researchers from Germany, Spain, Italy and the Czech Republic prepared an extremely clean and atomically well-defined oxide surface, on which they placed platinum nanoparticles. Using a highly sensitive detection method at the Synchrotron Radiation Source Elettra in Trieste the researchers could, for the first time, count the number of transferred electrons for particles up to hundreds of atoms. Using theoretical methods they could rationalize the effects and show how the charge transfer can be tuned to adjust the chemical properties. The latter would help to optimize a catalytic process and make more efficient use of materials and energy resources.
Counting Electrons on supported Nanoparticles
EAM Research Area D
Yaroslava Lykhach, Sergey M. Kozlov, Tomáš Skála, Andrii Tovt, Vitalii Stetsovych, Nataliya Tsud, Filip Dvořák, Viktor Johánek, Armin Neitzel, Josef Mysliveček, Stefano Fabris, Vladimír Matolín, Konstantin M. Neyman & Jörg Libuda
Nature Materials, 2016, 15, 284–288