title: Size-dependent electrocatalytic activity of gold nanoparticles on HOPG and highly boron-doped diamond surfaces.
abstract: Gold nanoparticles were prepared by electrochemical deposition on highly oriented pyrolytic graphite (HOPG) and boron-doped, epitaxial 100-oriented diamond layers. Using a potentiostatic double pulse technique, the average particle size was varied in the range from 5 nm to 30 nm in the case of HOPG as a support and between < 1 nm and 15 nm on diamond surfaces, while keeping the particle density constant. The distribution of particle sizes was very narrow, with standard deviations of around 20% on HOPG and around 30% on diamond. The electrocatalytic activity towards hydrogen evolution and oxygen reduction of these carbon supported gold nanoparticles in dependence of the particle sizes was investigated using cyclic voltammetry. For oxygen reduction the current density normalized to the gold surface (specific current density) increased for decreasing particle size. In contrast, the specific current density of hydrogen evolution showed no dependence on particle size. For both reactions, no effect of the different carbon supports on electrocatalytic activity was observed.
authors.affiliation: Department of Physics E19, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany. tine.bruelle@tum.de
authors.forename: Tine
authors.initials: T
authors.lastname: Brülle
authors.forename: Wenbo
authors.initials: W
authors.lastname: Ju
authors.forename: Philipp
authors.initials: P
authors.lastname: Niedermayr
authors.forename: Andrej
authors.initials: A
authors.lastname: Denisenko
authors.forename: Odysseas
authors.initials: O
authors.lastname: Paschos
authors.forename: Oliver
authors.initials: O
authors.lastname: Schneider
authors.forename: Ulrich
authors.initials: U
authors.lastname: Stimming
mesh_terms: D001895:Boron / Q000737:chemistry*; D002384:Catalysis; D018130:Diamond / Q000737:chemistry*; D004560:Electricity; D004563:Electrochemistry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D018625:Microscopy, Atomic Force; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D010316:Particle Size; D013499:Surface Properties; D013696:Temperature
chemical_list: D006046:Gold; D018130:Diamond; D006108:Graphite; D006859:Hydrogen; D001895:Boron; D010100:Oxygen