A Fe-doped Ni3S2 particle film as a high-efficiency robust oxygen evolution electrode with very high current density

The efficiency of water splitting is mainly limited by the low rate of the oxygen evolution reaction (OER) and it is thus of great importance but still remains a huge challenge to develop efficient OER catalysts capable of delivering high current densities at low overpotentials. Herein, we describe our recent finding that a Fedoped Ni3S2 particle film with 11.8% Fe-content hydrothermally grown on nickel foam (Fe-11.8%-Ni3S2/NF) behaves as a highly active robust oxygen evolution electrode in strongly alkaline media. This electrode needs an overpotential of only 253 mV to achieve 100 mA cm(-2) with a Tafel slope of 65.5 mV dec(-1) and maintains its catalytic activity for at least 14 h in 1 M KOH, and the NiOOH and FeOOH formed at the Fe-11.8%-Ni3S2 surface are the actual catalytic sites. Notably, it also operates efficiently and stably in 30 wt% KOH, capable of affording very high current densities of 500 and 1000 mA cm(-2) at small overpotentials of 238 and 269 mV, respectively, with a faradaic efficiency of 100%.