Incorporation of Fe/Co species on carbon: A facile strategy for boosting oxygen evolution

Scaling up new transition metal-based oxygen evolution catalysts for practical applications is still hindered by the complex synthesis route. In this study, in situ formation of electrocatalytic active species is simply achieved with a mixture ink composed of Nafion binder, commercially available acetylene black, and Fe3+/Co2+ ions. In this route, energy-intensive material preparation steps or noble metals are not required. The thus formed electrochemical active species can afford current density of 10 mA cm(-2) at a lower overpotential of 330 mV and showing a small Tafel slope of 55 mV dec(-1) in 1 M KOH, which is comparable to amounts of reported catalysts. It is proposed that the involved Fe3+/Co2+ ions are in situ transformed into hydroxides that further evolves into catalytic active species for oxygen evolution. The concept presented here is one of the simplest strategies to prepare highly active electrocatalysts for potential commercial application.