title: Metal-Support Interactions of Platinum Nanoparticles Decorated N-Doped Carbon Nanofibers for the Oxygen Reduction Reaction.
abstract: N-doped carbon materials are discussed as catalyst supports for the electrochemical oxygen reduction reaction (ORR) in fuel cells. This work deals with the preparation of Pt nanoparticles (NPs) supported on N-doped carbon nanofibers (N-CNF) from a polyaniline nanofiber (PANI NF) precursor, and investigates the ORR activity of the produced materials. Initially, Pt NPs are deposited on PANI NFs. The PANI NF precursors are characterized by near-edge X-ray absorption fine structure (NEXAFS) and transmission electron microscopy (TEM) measurements. It is shown, that in the PANI NF precursor materials electrons from the Pt are being transferred toward the π-conjugated systems of the aromatic ring. This strong interaction of Pt atoms with PANI explains the high dispersion of Pt NPs on the PANI NF. Subsequently, the PANI NF precursors are carbonized at different heat-treatment conditions resulting in structurally different N-CNFs which are characterized by NEXAFS, X-ray photoelectron spectroscopy (XPS) ,and TEM measurements. It is shown that an interaction between N-groups and Pt NPs exists in all investigated N-CNFs. However, the N-CNFs differ in the composition of the N-species and the dispersion of the Pt NPs. A small mean Pt NP size with a narrow size distribution is attributed to the presence of pyrdinic N-groups in the N-CNFs, whereas, for the N-CNFs with mainly graphitic and pyrrolic N-groups, an increase in the average Pt NP size with a broad size distribution is found. The ORR activity in alkaline media investigated by Koutecky-Levich analysis of rotating disk electrode measurements showed a largely enhanced ORR activity in comparison to a conventional Pt/C catalyst.
authors.affiliation: Institut für Angewandte Materialien-Energiespeichersysteme (IAM-ESS), Karlsruher Institut für Technologie (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.|Physikalische und Theoretische Chemie, Freie Universität Berlin , Takustrasse 3, 14195 Berlin, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Melke
authors.affiliation: Institut für Material- und Geowissenschaften, Technische Universität Darmstadt , Alarich-Weiss-Strasse 2, 64287 Darmstadt, Germany.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Peter
authors.affiliation: Institut für Material- und Geowissenschaften, Technische Universität Darmstadt , Alarich-Weiss-Strasse 2, 64287 Darmstadt, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Habereder
authors.affiliation: Institut für Material- und Geowissenschaften, Technische Universität Darmstadt , Alarich-Weiss-Strasse 2, 64287 Darmstadt, Germany.
authors.forename: Juergen
authors.initials: J
authors.lastname: Ziegler
authors.affiliation: Institut für Material- und Geowissenschaften, Technische Universität Darmstadt , Alarich-Weiss-Strasse 2, 64287 Darmstadt, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Fasel
authors.affiliation: Institut für Funktionelle Grenzflächen (IFG), Karlsruher Institut für Technologie (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Alexei
authors.initials: A
authors.lastname: Nefedov
authors.affiliation: Institut für Funktionelle Grenzflächen (IFG), Karlsruher Institut für Technologie (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.|Elettra-Sincrotrone Trieste S.C.p.A. , Strada Statale 14, 34012 Basovizza, Trieste, Italy.
authors.forename: Hikmet
authors.initials: H
authors.lastname: Sezen
authors.affiliation: Institut für Funktionelle Grenzflächen (IFG), Karlsruher Institut für Technologie (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Wöll
authors.affiliation: Institut für Angewandte Materialien-Energiespeichersysteme (IAM-ESS), Karlsruher Institut für Technologie (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Ehrenberg
authors.affiliation: Physikalische und Theoretische Chemie, Freie Universität Berlin , Takustrasse 3, 14195 Berlin, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Roth
keywords: NEXAFS; PANI; XPS; electrocatalysis; fuel cell; polyaniline