Facile electrodeposition of ternary Ni-Fe-Co alloy nanostructure as a binder free, cost-effective and durable electrocatalyst for high-performance overall water splitting.

Development of highly effective and stable electrocatalyst as full water electrolyzers is essential for the energy production process. In this study, binder-free and self-made Ni-Fe-Co nanostructure electrode was developed using electrodeposition method, and its electrocatalytic properties were investigated for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. The fabricated electrocatalyst exhibited excellent properties for the evolution of H2 and O2. Ni-Fe-Co nanostructure film required overpotentials of 91 mV for HER and 316 mV for OER in order to create a current density of 10 mA cm-2. Furthermore, the Tafel slope for HER and OER was measured as 86 and 43 mV/dec, respectively. In addition, the resulting electrode showed outstanding electrocatalytic stability, in which following a long period of electrolysis, the necessary overpotential to maintain a current density of 100 mA cm-2 remained constant. This bifunctional electrode enables alkaline water electrolyzers, which can provide a current density of 10 mA cm-2 under a cell voltage of 1.6 V. Such desirable performance of fabricated electrode as an electrocatalyst for full water splitting can be attributed to high active surface area factor, the synergistic effect of the elements, and rapid separation of bubbles from the electrode surface. This study provides a new method for the rapid construction of efficient electrocatalyst for renewable energy sources.