title: Cross-laboratory experimental study of non-noble-metal electrocatalysts for the oxygen reduction reaction.
abstract: Nine non-noble-metal catalysts (NNMCs) from five different laboratories were investigated for the catalysis of O(2) electroreduction in an acidic medium. The catalyst precursors were synthesized by wet impregnation, planetary ball milling, a foaming-agent technique, or a templating method. All catalyst precursors were subjected to one or more heat treatments at 700-1050 degrees C in an inert or reactive atmosphere. These catalysts underwent an identical set of electrochemical characterizations, including rotating-disk-electrode and polymer-electrolyte membrane fuel cell (PEMFC) tests and voltammetry under N(2). Ex situ characterization was comprised of X-ray photoelectron spectroscopy, neutron activation analysis, scanning electron microscopy, and N(2) adsorption and its analysis with an advanced model for carbonaceous powders. In PEMFC, several NNMCs display mass activities of 10-20 A g(-1) at 0.8 V versus a reversible hydrogen electrode, and one shows 80 A g(-1). The latter value corresponds to a volumetric activity of 19 A cm(-3) under reference conditions and represents one-seventh of the target defined by the U.S. Department of Energy for 2010 (130 A cm(-3)). The activity of all NNMCs is mainly governed by the microporous surface area, and active sites seem to be hosted in pore sizes of 5-15 A. The nitrogen and metal (iron or cobalt) seem to be present in sufficient amounts in the NNMCs and do not limit activity. The paper discusses probable directions for synthesizing more active NNMCs. This could be achieved through multiple pyrolysis steps, ball-milling steps, and control of the powder morphology by the addition of foaming agents and/or sulfur.
authors.affiliation: Institut National de la Recherche Scientifique, Energie, Materiaux & Telecommunications, 1650 Bd Lionel Boulet, Varennes, Quebec J3X 1S2, Canada. jaouen@emt.inrs.ca
authors.forename: Frédéric
authors.initials: F
authors.lastname: Jaouen
authors.forename: Juan
authors.initials: J
authors.lastname: Herranz
authors.forename: Michel
authors.initials: M
authors.lastname: Lefèvre
authors.forename: Jean-Pol
authors.initials: JP
authors.lastname: Dodelet
authors.forename: Ulrike I
authors.initials: UI
authors.lastname: Kramm
authors.forename: Iris
authors.initials: I
authors.lastname: Herrmann
authors.forename: Peter
authors.initials: P
authors.lastname: Bogdanoff
authors.forename: Jun
authors.initials: J
authors.lastname: Maruyama
authors.forename: Toru
authors.initials: T
authors.lastname: Nagaoka
authors.forename: Arnd
authors.initials: A
authors.lastname: Garsuch
authors.forename: Jeff R
authors.initials: JR
authors.lastname: Dahn
authors.forename: Tim
authors.initials: T
authors.lastname: Olson
authors.forename: Svitlana
authors.initials: S
authors.lastname: Pylypenko
authors.forename: Plamen
authors.initials: P
authors.lastname: Atanassov
authors.forename: Eugene A
authors.initials: EA
authors.lastname: Ustinov
mesh_terms: D002384:Catalysis; D002621:Chemistry / Q000379:methods; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004573:Electrolytes; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D015233:Models, Statistical; D010100:Oxygen / Q000737:chemistry*; D056951:Photoelectron Spectroscopy / Q000379:methods; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D011208:Powders / Q000737:chemistry; D013499:Surface Properties
chemical_list: D004573:Electrolytes; D011108:Polymers; D011208:Powders; D010100:Oxygen