Mesoporous carbon materials doped with Co, Fe and nitrogen as oxygen reduction reaction electrocatalysts for anion-exchange membrane fuel cell

Abstract

Mesoporous carbons (MCs) are prepared using dual-templating and doped with cobalt, iron and nitrogen for electrocatalytic applications and are characterised using various physico-chemical methods. Prepared materials are employed as oxygen reduction reaction (ORR) electrocatalysts and cathode catalysts of an anion-exchange membrane fuel cell (AEMFC). The MC materials are prepared using two novel and sustainable phenolic resin synthesis routes, while employing an easily removable soft template and MgO as a hard template to obtain feasible mesoporous texture. The content of MgO is varied in dual-templating to assess its influence on the porous structure and electrocatalytic properties. Doping is done via high-temperature pyrolysis using cobalt and iron acetate as transition metal sources and 1,10-phenanthroline as a nitrogen source. The physico-chemical characterisation shows that the preparation of MC materials and their subsequent doping has been successful. The initial assessment employing the rotating disc electrode method indicates that the synthesised catalyst materials exhibit very high electrocatalytic activity towards the ORR in alkaline media and good stability by applying 10,000 potential cycles. In AEMFC testing, the most promising cathode catalyst reveals excellent fuel cell performance by obtaining a peak power density above 500 mW cm^–2, almost the same performance as with commercial mesoporous Fe-N-C catalyst. Thus, the novel dual-templating approach taken herein enables to prepare sustainable non-precious metal electrocatalysts with feasible porous characteristics for the AEMFC application.