retour à l'accueil

Laboratoire d'Electrochimie Moleculaire, LEM, Paris

UMR CNRS - Université Paris Diderot - Paris France

Master Frontiers in Chemistry | UFR de Chimie - Université Paris Diderot - Paris 7 CNRS - Institut de chimie Université de Paris Master Chimie Sorbonne Paris Cité UFR de Chimie - Université Paris Diderot - Paris 7 CNRS - Institut de chimie
 |   Ecole Doctorale 388  |    Master Frontiers in Chemistry   |   C'Nano IdF   |   Respore  |
Université Paris Diderot
Université de Paris CNRS, Centre National de la Recherche Scientifique

Le LEM - Publications: Abstracts

Publication 842

ACS Energy Lett., 2, 2545-2551, 2017


In Situ Observation of the Formation and Structure of Hydrogen-Evolving Amorphous Cobalt Electrocatalysts


Benedikt Lassalle-Kaiser, Andrea Zitolo, Emiliano Fonda, Marc Robert, and Elodie Anxolabéhère-Mallart

Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette, France
Sorbonne Paris Cité, Laboratoire d’Electrochimie Moléculaire, UMR 7591 Université Paris Diderot - CNRS, 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France

We have used in situ and operando X-ray absorption spectroscopy at the cobalt K-edge to study the formation of cobalt nanoparticles from a molecular precursor, as well as their structural evolution under hydrogen-evolving electrocatalytic conditions. We show that these particles, which are about 100–150 nm in diameter overall, are made of an uncommon form of amorphous metallic cobalt, the smallest ordered unit being 1 nm clusters of ∼50 cobalt atoms. In aqueous solution, these porous particles are partly oxidized into cobalt(II), a fraction of which remains present as an outer shell during hydrogen evolution electrocatalysis, even at very high cathodic potentials. Our operando measurements show that the activity of the particles is correlated to the oxidized layer thickness, a thinner layer exposing a larger fraction of the active metallic cobalt and leading to a higher activity. These findings expand our current understanding of the solid–liquid interface in hydrogen evolution catalytic species in neutral pH and suggest new directions for the improvement of hydrogen-evolving catalytic system.

© 2005 LEM CréditsContactVenir au LEM