Institut Charles Gerhardt Montpellier, Laboratory for Aggregates, Interfaces and Materials for Energy, UMR 5253, CNRS, Université de Montpellier, Montpellier, France, Johnson Matthey Technology Centre, Sonning Common, Berkshire, United Kingdom, Commissariat à l'Energie Atomique - LETI, Campus Minatec, Grenoble Cedex, France

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 massspecific 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 metalnitrogen-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). © 2016 American Chemical Society.

Carbon dioxide, Catalysts, Crystalline materials, Electrolytes, Electrolytic reduction, Fuel cells, Manganese, Metals, Organometallics, Oxygen, Pollution control, Polyelectrolytes, Proton exchange membrane fuel cells (PEMFC), Secondary batteries, Solid electrolytes, Acidic electrolytes, Carbon dioxide reduction, Hydrogen evolution, Metal organic framework, Polymer electrolyte fuel cells, Structural descriptors, Structure property relationships, Zeolitic imidazolate frameworks, C (programming language), carbon, iron, metal organic framework, nitrogen, unclassified drug, zeolitic imidazolate framework, Article, catalyst, chemical composition, chemical structure, controlled study, hydrogen evolution, molecular probe, quantitative structure property relation, stoichiometry, structure activity relation, surface property, synthesis