The development of stable and efficient oxygen evolutional electrocatalysts is fundamental to the production of hydrogen by water electrolysis. However, so far the majority of electrocatalysts require a substantial overpotential (η) (approximately >250 mV) to catalyze the bottleneck oxygen evolution reaction (OER). To overcome this large overpotential for OER, herein we report the growth of nickel-cobalt-selenide (NiCoSe 2 ) nanosheets over 3D nickel foam (NF) via a facile and scalable electrodeposition method. The resulting 3D NiCoSe 2 /NF hybrid electrode requires an overpotential of merely 183 mV to reach the current density (J) of 10 mA cm -2 . To the best of our knowledge, this is the lowest η value reported so far for any earth-abundant material-based OER electrocatalyst to attain the same current density. Moreover, a significant reduction in Tafel slope (88 mV dec -1 ) is observed between bare NF and NiCoSe 2 /NF. Hence, as a result, the 3D hybrid NiCoSe 2 /NF OER electrode outperforms the previously reported electrocatalysts including the expensive state-of-the-art OER electrocatalysts like RuO 2 and IrO 2 . Such enhancement in the OER catalytic efficiency of NiCoSe 2 nanosheets over NF can be attributed to its enormous electrochemical active surface area (ECSA) (108 cm 2 ), large roughness factor (270), highly conductive NF substrate, and the presence of multiple catalytically active OER species (NiOOH and CoOOH) on its surface. In addition, 3D hybrid NiCoSe 2 /NF electrocatalyst was tested for hydrazine oxidation for its bifunctional utilization. Much lower onset potential values (-0.7 V vs SCE) and high current densities (>200 mA cm -2 ) are observed for 3D hybrid NiCoSe 2 /NF when benchmarked against bare NF (-0.4 V and <50 mA cm -2 ). Furthermore, 3D hybrid NiCoSe 2 /NF OER electrode shows excellent stability of 50 h for continuous OER in strongly alkaline solutions while maintaining its enormous ECSA, chemical composition, and structural morphology. The excellent bifunctional electrocatalytic activity, long-term stability, and facile preparation method enable NiCoSe 2 /NF hybrid electrode to be a viable candidate for its widespread use in various water-splitting technologies.
All Science Journal Classification (ASJC) codes
- Environmental Chemistry
- Chemical Engineering(all)
- Renewable Energy, Sustainability and the Environment