Phyto-inspired Cu/Bi oxide-based nanocomposites: synthesis, characterization, and energy relevant investigation

A modified and sustainable approach is reported in this research for the synthesis of a spherical-shaped CuO-Bi₂O₃ electrode material for electrochemical studies. Aqueous extract derived from the plant Amaranthus viridis L. (Amaranthaceae) (AVL) was used as a reducing agent for morphological control of the synthesis of CuO-Bi₂O₃ nanocomposites. The modified nanomaterial revealed an average crystal size of 49 ± 2 nm, which matches very well with scanning electron microscopy (SEM) findings. Furthermore, the synthesized material was characterized using Fourier-transform infrared spectroscopy, field emission SEM and energy-dispersive spectroscopy. The optical band gap energy of 3.45 eV was calculated using a Tauc plot. Finally, the bioorganic framework-derived CuO-Bi₂O₃ electrode was tested for energy generating and storage applications and the results revealed a capacitance of 389 F g^-1 by cyclic voltammetry, with a maximum energy density of 12 W h kg^-1 and power density of 5 kW kg^-1. Hydrogen evolution reaction and oxygen evolution reaction studies showed good potential of CuO-Bi₂O₃ as an electrocatalyst for water splitting, with maximum efficiency of the electrode up to 16.5 hours.