Stability of metallo-porphyrin networks under oxygen reduction and evolution conditions in alkaline media

authored by: Diana Hötger, Markus Etzkorn, Claudius Morchutt, Benjamin Wurster, Jan Dreiser, Sebastian Stepanow, Doris Grumelli, Rico Gutzler, Klaus Kern
Abstract: Transition metal atoms stabilised by organic ligands or as oxides exhibit promising catalytic activity for the electrocatalytic reduction and evolution of oxygen. Built-up from earth-abundant elements, they offer affordable alternatives to precious-metal based catalysts for application in fuel cells and electrolysers. For the understanding of a catalyst's activity, insight into its structure on the atomic scale is of highest importance, yet commonly challenging to experimentally access. Here, the structural integrity of a bimetallic iron tetrapyridylporphyrin with co-adsorbed cobalt electrocatalyst on Au(111) is investigated using scanning tunneling microscopy and X-ray absorption spectroscopy. Topographic and spectroscopic characterization reveals structural changes of the molecular coordination network after oxygen reduction, and its decomposition and transformation into catalytically active Co/Fe (oxyhydr)oxide during oxygen evolution. The data establishes a structure-property relationship for the catalyst as a function of electrochemical potential and, in addition, highlights how the reaction direction of electrochemical interconversion between molecular oxygen and hydroxyl anions can have very different effects on the catalyst's structure.
External Organisation(s): Max Planck Institute for Solid State Research (MPI-FKF)
Technische Universität Braunschweig
École polytechnique fédérale de Lausanne (EPFL)
Paul Scherrer Institut (PSI)
ETH Zurich
Universidad Nacional de La Plata
Type: Article
Journal: Physical Chemistry Chemical Physics
Volume: 21
Pages: 2587-2594
No. of pages: 8
ISSN: 1463-9076
Publication date: 2019
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy(all), Physical and Theoretical Chemistry
Electronic version(s): https://doi.org/10.1039/c8cp07463a (Access: Open)

BibTeX

@article{131145fca0c249648f49881bb8c5895a,
title = "Stability of metallo-porphyrin networks under oxygen reduction and evolution conditions in alkaline media",
abstract = "Transition metal atoms stabilised by organic ligands or as oxides exhibit promising catalytic activity for the electrocatalytic reduction and evolution of oxygen. Built-up from earth-abundant elements, they offer affordable alternatives to precious-metal based catalysts for application in fuel cells and electrolysers. For the understanding of a catalyst's activity, insight into its structure on the atomic scale is of highest importance, yet commonly challenging to experimentally access. Here, the structural integrity of a bimetallic iron tetrapyridylporphyrin with co-adsorbed cobalt electrocatalyst on Au(111) is investigated using scanning tunneling microscopy and X-ray absorption spectroscopy. Topographic and spectroscopic characterization reveals structural changes of the molecular coordination network after oxygen reduction, and its decomposition and transformation into catalytically active Co/Fe (oxyhydr)oxide during oxygen evolution. The data establishes a structure-property relationship for the catalyst as a function of electrochemical potential and, in addition, highlights how the reaction direction of electrochemical interconversion between molecular oxygen and hydroxyl anions can have very different effects on the catalyst's structure.",
author = "Diana H{\"o}tger and Markus Etzkorn and Claudius Morchutt and Benjamin Wurster and Jan Dreiser and Sebastian Stepanow and Doris Grumelli and Rico Gutzler and Klaus Kern",
note = "Publisher Copyright: {\textcopyright} 2019 the Owner Societies.",
year = "2019",
doi = "10.1039/c8cp07463a",
language = "English",
volume = "21",
pages = "2587--2594",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",
number = "5",
}