Co3O4 nanoparticles synthesized with rotten-grape extract for use in supercapacitors and oxygen evolution devices

Phytochemicals in grape fruit juice have never been considered as potential sources of surface modification, shape modification, and energy storage. In our study, we demonstrate the hydrothermal synthesis of Co 3 O 4 nanostructures from grape fruit extracts. X-ray diffraction analysis revealed that Co 3 O 4 nanostructures exhibit a cubic phase, while Fourier transform infrared spectroscopy identified several functional groups. An analysis of Co 3 O 4 nanostructures using a scanning electron microscope revealed that uniformly distributed nanoparticles of Co 3 O 4 were trapped in the carbon content of the spices during calcination. UV–visible spectrometer analysis of Co 3 O 4 nanostructures reveals a wide range of optical bands. It was found that one mL of grape fruit juice provided the lowest optical band gap of 2.51 eV for Co 3 O 4 nanostructures. Nanostructures of Co 3 O 4 were studied under alkaline conditions for use in supercapacitors and oxygen evolution reactions. An aqueous solution containing 1 mL of assisted Co 3 O 4 nanostructures exhibited an overpotential of 290 mV at a current density of 10 mA cm −2 in 1 M KOH. In addition, they showed a Tafel slope of 80 mV dec −1 . When dissolved in 3 M KOH electrolyte, grape fruit juice assisted Co 3 O 4 nanostructures showed a specific capacitance of 867 F/g at 1.5 A/g in 3 M KOH aqueous solution. A specific capacitance retention percentage of about 101.1 % was achieved after 40000 galvanic charge-discharge cycles. It has been shown that the total photochemistry of biomass waste can be tuned and enhanced to enhance the functional properties of nanostructures derived from rotten grape fruit extract in order to develop functional materials with high performance for a wide range of applications. • Rotten grapes modified the shape and particle size of Co 3 O 4 . • Rotten grapes reduced the optical band gap of Co 3 O 4 nanostructures. • An overpotential of 290 mV was noticed at 10 mAcm −2 during OER. • ASC device exhibited a specific capacitance of 867F/g at 1.5A/g.