Hierarchical NiCo2S4 Nanowire Arrays Supported on Ni Foam: An Efficient and Durable Bifunctional Electrocatalyst for Oxygen and Hydrogen Evolution Reactions |
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Authors: | Arumugam Sivanantham Pandian Ganesan Sangaraju Shanmugam |
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Affiliation: | Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, Republic of Korea |
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Abstract: | A recent approach for solar‐to‐hydrogen generation has been water electrolysis using efficient, stable, and inexpensive bifunctional electrocatalysts within strong electrolytes. Herein, the direct growth of 1D NiCo2S4 nanowire (NW) arrays on a 3D Ni foam (NF) is described. This NiCo2S4 NW/NF array functions as an efficient bifunctional electrocatalyst for overall water splitting with excellent activity and stability. The 3D‐Ni foam facilitates the directional growth, exposing more active sites of the catalyst for electrochemical reactions at the electrode–electrolyte interface. The binder‐free, self‐made NiCo2S4 NW/NF electrode delivers a hydrogen production current density of 10 mA cm–2 at an overpotential of 260 mV for the oxygen evolution reaction and at 210 mV (versus a reversible hydrogen electrode) for the hydrogen evolution reaction in 1 m KOH. This highly active and stable bifunctional electrocatalyst enables the preparation of an alkaline water electrolyzer that could deliver 10 mA cm–2 under a cell voltage of 1.63 V. Because the nonprecious‐metal NiCo2S4 NW/NF foam‐based electrodes afford the vigorous and continuous evolution of both H2 and O2 at 1.68 V, generated using a solar panel, they appear to be promising water splitting devices for large‐scale solar‐to‐hydrogen generation. |
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Keywords: | alkaline water electrolyzer hydrogen evolution NiCo2S4 oxygen evolution solar‐to‐hydrogen generation |
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