Cobalt-, iron- and nitrogen-containing ordered mesoporous carbon-based catalysts for anion-exchange membrane fuel cell cathode

Abstract

Cobalt-, iron- and nitrogen-doped ordered mesoporous carbon (OMC)-based electrocatalysts are prepared, characterized, and used as cathode catalysts in anion-exchange membrane fuel cell (AEMFC). The OMC material is synthesized using a green and simple route via soft-template method and without the usage of harsh chemicals. To study the effect of porous structure of carbon support on the electrocatalytic properties, the OMC material is also mixed either with carbide-derived carbon (CDC) or carbon nanotubes (CNTs). Doping of carbon nanomaterials is done via high-temperature pyrolysis in the presence of cobalt and iron acetate as well as 1,10-phenanthroline. The physico-chemical characterization shows that the preparation of OMC and subsequent doping of nanocarbons has been successful, and the catalysts contain single-atom M-Nx centres. The initial assessment employing the rotating disc electrode method indicates that all three doped catalyst materials exhibit very high electrocatalytic activity toward the oxygen reduction reaction (ORR) in alkaline media and good stability after 10,000 potential cycles. In AEMFC testing with AEMION+ anion exchange membrane, the prepared cathode catalysts show good performance with CoFe-N-OMC/CNT obtaining the highest peak power density of 336 mW cm–2. Slightly lower AEMFC performance observed for CoFe-N-OMC and CoFe-N-OMC/CDC cathodes indicates that it is influenced by the catalyst's porous structure. It can be concluded that the OMC-based materials are promising cathode catalysts for AEMFC application.