A Novel Approach for Efficient Water Oxidation and Supercapacitor Applications Based on Morphologically Transformed, Surface Rich Oxygen Vacancies of Co₃o₄ Nanostructures Co-Synthesized with Potato Starch Peel Extract

An emerging material, cobalt oxide (Co₃O₄) may be useful for a number of promising technological applications, including energy conversion and storage devices. Among the limiting factors of Co₃O₄ are its small surface area as well as its poor electrical conductivity. Our study describes the controllable synthesis of Co₃O₄ nanostructures using a renewable source in the form of potato peel extract, which is an abundant and inexpensive source of starch. Surface active features were observed along with significant changes in structure, crystal orientation, and surface chemical composition. As a result of detailed characterization of phase purity, shape orientation, crystal structure, and surface chemical composition, the as-synthesized Co₃O₄ nanostructures were fabricated as electrode materials and investigated for supercapacitors and oxygen evolution reactions (OER) applications. The optimized Co₃O₄ nanostructures comprising 10 mL of potato peel extract have demonstrated a highly improved pseudo-capacitance performance with a specific capacitance of 1453.13Fg^{− 1} and a specific energy density of 32.29 Wh/Kg at a current density of 1.25 Ag^{− 1} in 3.0 M KOH electrolytic solution. It was determined that the electrode materials have a cycling stability of 96–99% over 30,000 repeatable cycles with a columbic efficiency of 95–100%, which indicates the high practicality of the electrode materials. The OER performance of 10 mL of potato peel extract assisted Co₃O₄ nanostructures was also evaluated using 1.0 M KOH. An fabricated Co₃O₄ nanostructure derived from potato peel extract exhibited an overpotential of 260 mV at 10 mAcm^{− 2} and a Tafel slope of 72 mV dec^{− 1} in 1.0 M KOH. Furthermore, the constructed electrode material was extremely durable for a period of 30 h at two different constant-current densities of 20 mAcm^{− 2} and 40 mAcm^{− 2}. Among the attributes that contribute to the superb performance of the newly developed Co₃O₄ electrode materials are the fascinating morphology, the reduced size, the enriched active surfaces, and the high degree of compatibility. Overall, the findings of this study establish that potato peel extract can serve as a valuable source of starch for the development of next-generation of electrode materials for efficient energy storage and conversion systems.