Highly efficient and stable bifunctional electrocatalyst for water splitting on Fe–Co3O4/carbon nanotubes

Abstract

Replacement of precious platinum (Pt) or ruthenium oxide (RuO2) catalysts with efficient, cheap and durable electrocatalysts from earth-abundant elements bifunctional alternatives would be significantly beneficial for key renewable energy technologies including overall water splitting and hydrogen fuel cells. Despite tremendous efforts, developing bifunctional catalysts with high activity at low cost still remain a great challenge. Here, we report a nanomaterial consisting of core-shell-shaped Fe–Co3O4 grown on carbon nanotubes (Fe–Co3O4/CNTs) and employed as a bifunctional catalyst for the simultaneous electrocatalysts on oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The Fe–Co3O4/CNTs electrocatalyst outperforms the commercial RuO2 catalyst in activity and stability for OER and approaches the performance of Pt/C for HER. Particularly, it shows superior electrocatalytic activity with lowering overpotentials of 120 mV at 10 mA cm−2 for HER and of 300 mV at 10 mA cm−2 for OER in 1 M KOH solution. The superior catalytic activity arises from unique core-shell structure of Fe–Co3O4 and the synergetic chemical coupling effects between Fe–Co3O4 and CNTs.