A self-supported porous WN nanowire array: an efficient 3D electrocatalyst for the hydrogen evolution reaction

The development of non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) has attracted much attention. Metal nitrides have been considered as promising alternatives in recent years. Nevertheless, the preparation of tungsten nitride still suffers from disadvantages such as environmentally unfriendly sources and poor morphologies, which induce a relatively low activity. Herein we employed clean N2-plasma to develop a 3D WN nanowire array on carbon cloth (WN NW/CC) with a porous structure. As expected, the resulting WN NW/CC is highly active, giving a small η10 (overpotential to drive a current of 10 mA cm−2) of 134 mV and a Tafel slope of 59.6 mV dec−1 in acidic solution, and an η10 of 130 mV and a Tafel slope of 57.1 mV dec−1 in alkaline solution, respectively. Additionally, it maintains its catalytic activity for at least 14 500 s in both acidic and alkaline media.