Pulse Electrodeposition of a Superhydrophilic and Binder-Free Ni-Fe-P Nanostructure as Highly Active and Durable Electrocatalyst for Both Hydrogen and Oxygen Evolution Reactions.

Development and fabrication of electrodes with favorable electrocatalytic activity, low-cost, and excellent electrocatalytic durability are one of the most important issues in the hydrogen production area using the electrochemical water splitting process. We use the pulse electrodeposition method as a versatile and cost-effective approach to synthesize three-dimensional Ni-Fe-P electrocatalysts on nickel nanostructures under various applied frequencies and duration times, in which nanostructures exhibit excellent intrinsic electrocatalytic activity. Benefiting from the three-dimensional structure, as well as the simultaneous presence of the three elements nickel, iron, and phosphorus, the electrode fabricated at the optimal conditions has indicated outstanding electrocatalytic activity with a η of 66 and 198 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, in a 1.0 M KOH solution. Also, the water electrolysis cell constructed with this electrode and tested as a bifunctional electrode exhibited 1.508 V for 10 mA cm in overall water splitting. In addition, the lowest amount of potential change in 100 mA cm was observed for HER and OER, indicating excellent electrocatalytic stability. This study proposes a binder-free and economical technique for the synthesis of three-dimensional electrocatalysts.