NiO bio-composite materials: Photocatalytic, electrochemical and supercapacitor applications

Synthesis based on biomaterial technology has high potential in structural applications. Blending metal oxides with plant extract is an attractive alternative for preparing materials with superior material properties. Here, we report for the first time, the synthesis of NiO bio-composite materials by employing Aloe vera leaf extract. The work mainly highlights the synergistic influence of biomolecules of Aloe vera plant on the electrochemical and photocatalytic properties of NiO. The structure, morphology, band gap and bonding features of NiO bio-composites were characterized by XRD, Electron Microscopy, UV-DRS and FT-IR techniques, respectively. The average crystallite size of the composites was within 60 nm. FT-IR spectra confirmed the strong bonding interactions between biomolecules and NiO. A maximum band gap of 3.88 eV with a good thermal stability for the synthesized composites was observed. The addition of biomolecules to NiO resulted in the improvement of the reversibility of the electrode by reducing the anodic (Epa) and cathodic (Epc) peak potential difference in KOH electrolyte. Also, the composite exhibited greater stability due to recyclability and less resistance even after 1000 charge-discharge cycles, revealing a stable electrode material for supercapacitors applications. The photocatalytic experiments confirmed a maximum of 95% dye degradation efficiency by the composite for AR88 dye. It was also found that 50 % of dye degradation occurred within 74.61 min. The encouraging results project out the potential of the synthesized NiO-biocomposites to be a better supercapacitor and photocatalyst.