Layer-structured NiFe nanosheets on CoNi nanowires for enhanced oxygen evolution reaction

Efficient electrocatalysts are critical for the oxygen evolution reaction (OER) that occurs during water electrolysis. Herein, a simple and low-cost strategy of assembling CoNi nanowire arrays with NiFe nanosheets on flexible carbon cloth (CC) support as an efficient OER catalyst is developed. This unique ‘nanosheets on nanowires’ structure design increases its specific surface area, enabling access to more active sites. The resulting NiFe@H-CoNi/CC catalyst exhibits excellent OER activity (280 mV overpotential at 100 mA cm−2) with a Tafel slope of 36 mV dec−1 and also has outstanding durability at high current operation conditions (over 100 h at 100 mA cm−2). Moreover, in-situ Raman analysis suggests that the NiOOH is the realistic OER active phase. This ‘nanosheet on nanowire’ design gives a means for fabricating OER catalysts that are both high-performance and long-lasting.