Fe doped skutterudite-type CoP3 nanoneedles as efficient electrocatalysts for hydrogen and oxygen evolution in alkaline media

Non-noble-metal catalysts are the key point for the development of water splitting to produce hydrogen, a process which can be used to overcome the energy crisis. In this paper, we investigated water splitting in alkaline environments using skutterudite-type cobalt phosphide (CoP 3 ) nanoneedle arrays fabricated on carbon cloth. A moderate amount of iron is doped into pristine CoP 3 , and the resulting Co 1− x Fe x P 3 shows a significant enhancement for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) compared with the pristine CoP 3 . Co 0.7 Fe 0.3 P 3 displays the best HER performance, with an overpotential of 167 mV vs. reversible hydrogen electrode (RHE) to reach a current density of 10 mA cm −2 ( η 10 ) and a Tafel slope of 65.1 mV dec −1 . Co 0.7 Fe 0.3 P 3 also shows the best OER catalytic performance, reaching a current density of 50 mA cm −2 ( η 50 ) at an overpotential of 330 mV vs. RHE. Our results indicate that simple second metal element doping is an effective way to improve the HER and OER performance of skutterudite-type electrocatalysts in alkaline media.