A binder- and carbon-free hydrogen evolution electro-catalyst in alkaline media based on nitrogen-doped Ni(OH)2 nanobelts/3D Ni foam

Abstract

Designing a simple method to prepare a binder- and carbon-free catalyst with a highly efficient and stable hydrogen evolution electro-catalytic performance in the alkaline media is necessary and urgent. Herein, we develop a low-temperature hydrothermal nitridation and crystal transformation process for the preparation of nitrogen-doped Ni(OH)2 nanobelts decorated on 3D Ni foam (N-Ni(OH)2/NF), where the precursor of amorphous Ni(OH)2/3D Ni foam is fabricated by a simple electrodeposition process. The hydrogen evolution process of our N-Ni(OH)2/NF electrode is studied by using a classical three-electrode electrochemical measurement in the alkaline media. The as-prepared N-Ni(OH)2/NF electrode exhibits a small onset overpotential of 178 mV at 100 mA·cm−2 along with the superior electro-catalytic durability and stability after 10,000 cycles and 24-h continuous operation. The good electrocatalytic hydrogen evolution performance of the N-Ni(OH)2/NF electrode may be attributed to the absence of inactive materials (conducting carbon and binder), the high electrochemical active sites with a double-layer capacitance (Cdl) of 9.33 mF·cm−2, the doping effect of nitrogen atom into Ni(OH)2 crystalline, and the crystal transformation of Ni(OH)2. More importantly, this strategy may be used to modify other transition metal oxides/hydroxides/sulfides/phosphides/selenides for the improved electrocatalytic hydrogen evolution performance.