title: Structural Descriptors of Zeolitic-Imidazolate Frameworks Are Keys to the Activity of Fe-N-C Catalysts.
abstract: Active and inexpensive catalysts for oxygen reduction are crucially needed for the widespread development of polymer electrolyte fuel cells and metal-air batteries. While iron-nitrogen-carbon materials pyrolytically prepared from ZIF-8, a specific zeolitic imidazolate framework (ZIF) with sodalite topology, have shown enhanced activities toward oxygen reduction in acidic electrolyte, the rational design of sacrificial metal-organic frameworks toward this application has hitherto remained elusive. Here, we report for the first time that the oxygen reduction activity of Fe-N-C catalysts positively correlates with the cavity size and mass-specific pore volume in pristine ZIFs. The high activity of Fe-N-C materials prepared from ZIF-8 could be rationalized, and another ZIF structure leading to even higher activity was identified. In contrast, the ORR activity is mostly unaffected by the ligand chemistry in pristine ZIFs. These structure-property relationships will help identifying novel sacrificial ZIF or porous metal-organic frameworks leading to even more active Fe-N-C catalysts. The findings are of great interest for a broader application of the class of inexpensive metal-nitrogen-carbon catalysts that have shown promising activity also for the hydrogen evolution (Co-N-C) and carbon dioxide reduction (Fe-N-C and Mn-N-C).
authors.affiliation: Institut Charles Gerhardt Montpellier, Laboratory for Aggregates, Interfaces and Materials for Energy, UMR 5253, CNRS, Université de Montpellier , 34095 Montpellier, France.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Armel
authors.affiliation: Johnson Matthey Technology Centre , Sonning Common, Berkshire RG4 9NH, United Kingdom.
authors.forename: Sheena
authors.initials: S
authors.lastname: Hindocha
authors.affiliation: Institut Charles Gerhardt Montpellier, Laboratory for Aggregates, Interfaces and Materials for Energy, UMR 5253, CNRS, Université de Montpellier , 34095 Montpellier, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Salles
authors.affiliation: Johnson Matthey Technology Centre , Sonning Common, Berkshire RG4 9NH, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Bennett
authors.affiliation: Institut Charles Gerhardt Montpellier, Laboratory for Aggregates, Interfaces and Materials for Energy, UMR 5253, CNRS, Université de Montpellier , 34095 Montpellier, France.
authors.forename: Deborah
authors.initials: D
authors.lastname: Jones
authors.affiliation: Institut Charles Gerhardt Montpellier, Laboratory for Aggregates, Interfaces and Materials for Energy, UMR 5253, CNRS, Université de Montpellier , 34095 Montpellier, France.
authors.forename: Frédéric
authors.identifier: 0000-0001-9836-3261
authors.initials: F
authors.lastname: Jaouen