Self-Supported Hierarchical FeCoNi-LTH/NiCo2O4/CC Electrodes with Enhanced Bifunctional Performance for Efficient Overall Water Splitting.

The development of advanced earth-abundant electrocatalysts for hydrogen production is highly desirable. In this paper, we report the design and synthesis of a novel and highly efficient electrode of NiCo2O4 nanoneedles decorated with FeCoNi layered ternary hydroxides supported on carbon cloth (FeCoNi-LTH/NiCo2O4/CC) by a facile and efficient two-step approach. It exhibits superior bifunctional catalytic activities for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media, due to the special structure and strong synergies. The FeCoNi-LTH/NiCo2O4/CC obtains an onset overpotential of 240 mV and an overpotential of 302 mV at the current density of 50 mA cm-2 for OER, which is superior to RuO2. It also efficiently catalyzes HER with onset overpotential of 96 mV and overpotential of 151 mV to achieve a current density of 20 mA cm-2. Serving as both cathode and anode in a two-electrode water splitting system, FeCoNi-LTH/NiCo2O4/CC only requires an overpotential of 1.65 V at current density of 50 mA cm-2. The cell exhibits outstanding stability as well, indicating that FeCoNi-LTH/NiCo2O4/CC is a befitting material to be utilized as effective bifunctional catalysts for overall water splitting.