Abstract
The dearth of efficient, robust, and economical electrocatalysts for water oxidation is dubiously the key obstacle for renewable energy devices, so synthesis of efficient, and cost-effective metal-based water oxidation catalysts is vital. Herein, Co3O4, Co9S8 catalysts and their heterostructure Co3O4/Co9S8 were synthesized and evaluated as water oxidation electrocatalysts. The characterization of Co3O4, Co9S8, and Co3O4/Co9S8 electrocatalysts was performed using Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction techniques. The heterostructure Co3O4/Co9S8 (1.46 V) exhibited water oxidation electrocatalysis at extremely low onset potential compared to Co3O4 (1.58 V), and Co9S8 (1.48 V) catalysts. A 281 mV overpotential required to attain a current density of 50 mA cm−2 in alkaline solution (1 M KOH), outperforming most of Co-based benchmark electrocatalysts. Further, the Co3O4/Co9S8 heterojunction demonstrated catalytic activity with small Tafel slope of 37 mV dec−1. The finding of electrochemical studies involving controlled potential electrolysis and long-term stability are projected to steer the future advancement in constructing efficient, economical, stable, and earth-abundant metal-based water oxidation catalysts.
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•A novel Co3O4/Co9S8 catalyst exhibited the excellent performance for water oxidation.•The Co3O4/Co9S8 catalyst exhibits a favorable OER with 281 mV of overpotential.•A small Tafel slope of 37 mV dec−1 achieved for Co3O4/Co9S8 electrocatalyst in alkaline media.•The Co3O4/Co9S8 catalyst has low Tafel slope and overpotential than most state of art Co-based electrocatalysts.