Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 10: Metal/Water Interfaces: Structure and Reactivity

O 10.14: Vortrag

Montag, 16. März 2015, 18:15–18:30, HE 101

Size dependent electrocatalytic activity of Pt nanoparticles on Ru(0001) supported graphene - hydrogen evolution reaction — •Jens Klein, Albert K. Engstfeld, Sylvain Brimaud, and R. Jürgen Behm — Ulm University, Institute of Surface Chemistry and Catalysis, D-89069 Ulm, Germany

In water electrolysers and fuel cell technology, carbon supported Platinum nanoparticles are the state-of-the-art catalyst for the hydrogen evolution reaction. The performance of this catalyst depends sensitively on the size, density, shape and stability of the Pt nanoparticles.^[1] To get a more detailed understanding on the structure | activity relationship of this particular system, we present results of a model catalyst study on Pt nanoparticles on Ru(0001) supported graphene, investigated in a combined ultra high vacuum (UHV) - electrochemical flow cell setup. The graphene layer was prepared under UHV by ethylene decomposition on Ru(0001) at 1050 K. Lateral Pt nanoparticle arrays with well defined size distributions were grown by physical vapor deposition and characterized by scanning tunneling microscopy (STM). The sizes of the Pt nanoparticles are below 3 nm and they consist of 10-80 atoms in average. After structural analysis, the model electrodes were transferred to an electrochemical flow cell, attached to the UHV system, to investigate their electrocatalytic activity during the hydrogen evolution reaction (HER) by cyclic voltammetry. Finally, to assure that the particles are stable in the electrocatalytic environment, the model electrodes were again characterized by STM in UHV afterwards. [1] M.T.M. Koper, Nanoscale 3 (2011) 2054.