Bifunctional Iron-Nickel Nitride Nanoparticles as Flexible and Robust Electrode for Overall Water Splitting

•3D iron-nickel nitride (Ni3FeN) nanoparticles grown on carbon cloth are developed.•The Ni3FeN shows outstanding activities toward both HER and OER in alkaline media.•An advanced water electrolyzer based on the Ni3FeN for water splitting is achieved.

The state-of-the-art and stable electrocatalysts with non-noble metal elements are exceedingly desirable for hydrogen/oxygen production from water splitting. Herein, three-dimensional (3D) iron-nickel nitride nanoparticles grown on carbon cloth (Ni3FeN-NPs) are developed as a flexible bifunctional electrocatalyst for overall water splitting. The as-prepared Ni3FeN-NPs show outstanding electrocatalytic activities toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 M KOH solution, with low overpotentials of 238 and 241 mV at 10 mA/cm2, Tafel slopes of 46 and 59 mV/dec, respectively. Moreover, an advanced water electrolyzer based on the Ni3FeN-NPs electrodes as anode and cathode is assembled and could achieve overall water splitting with a cell voltage of 1.81 V at 10 mA/cm2. Also, the as-fabricated water electrolyzer exhibits stable electrocatalytic performance without decreasing in 1 M KOH after 130 h even at the foldable state.

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