Biogenic Synthesis and Characterization of ZrO₂-La₂O₃ and Study of its Scope in Energy Based Applications: Supercapacitors & Water Splitting

This research work explores the role of organic metabolites of Amaranthus viridis in biogenic synthesis of binary composite of ZrO₂-La₂O₃. The structural and compositional studies of the newly synthesized composite was carried out using various characterization techniques which revealed the unique rod type arrangement of spherical shaped particles with particle size in range of 70–88 nm and crystallite size of 28.8 nm. The band gap value of 2.5 eV was obtained for ZrO₂-La₂O₃ using Tauc plot, whereas no elemental impurity was observed through Energy-dispersive X-ray spectroscopy. The ZrO₂-La₂O₃ based composite was further investigated for its scope in energy based studies as an electrode material. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) was carried out using Linear sweep voltammetry and electrochemical impedance spectroscopy. The obtained results revealed better performance of fabricated electrode material for HER with an overpotential value of 148 mV. Furthermore, cyclic voltammetry and galvanostatic charge discharge techniques were used to analyze the energy storage potential of ZrO₂-La₂O₃ based electrode which showed the excellent capacitance behavior with capacitance value of 870.9 F/g at 2 mV/s. The exceptional cyclic stability up to 2000th cycles further endorsed the potential of biogenic synthesis and fabricated electrode on commercial level.