NiCo₂S₄nanowires array as an efficient bifunctional electrocatalyst for full water splitting with superior activity

The present communication reports the topotactic conversion of NiCo2O4 nanowires array on carbon cloth (NiCo2O4 NA/CC) into NiCo2S4 NA/CC, which is used as an efficient bifunctional electrocatalyst for water splitting with good durability and superior activity in 1.0 M KOH. This NiCo2S4 NA/CC electrode produces 100 mA cm(-2) at an overpotential of 305 mV for hydrogen evolution and 100 mA cm(-2) at an overpotential of 340 mV for oxygen evolution. To afford a 10 mA cm(-2) water-splitting current, the alkaline water electrolyzer made from NiCo2S4 NA/CC needs a cell voltage of 1.68 V, which is 300 mV less than that for NiCo2O4 NA/CC, and has good stability.