Effect of fractional graphite alloying on the properties of aloe-vera mediated green-synthesized NiO_x-C composite

Abstract

This study emphasizes the synthesis of nickel oxide (NiO_x+ C) nanoparticles with varied graphite (C) proportions (1%, 2.5%, 5%, 7.5%, and 10%) using Aloe-Vera natural extract as a green reducing agent. Prepared NiO_x+ C nanostructures exhibited consistent X-ray diffraction patterns with no additional C peak, signifying enhanced interlayer spacing. The crystalline size (D_p) decreased from 27 nm to 20 nm with an increase in the amount of carbon (C). The determined bandgap (E_g) was 2 eV higher than bulk material due to formation extra energy level at defect sites. The shoulder peak at 1620 cm⁻¹ agrees with the disorder-induced band from C and second-order bands of C at about 2700 cm⁻¹ for NiO_x+ C. FESEM images confirm the hexagonal morphology. Not much particle aggregation was observed except for 10% C content. The selected area electron diffraction (SAED) confirms the existence of NiO_x crystalline orientations including planes (111), (200), (220), (311), and (222).

KEYWORDS:

• Nickel oxide
• graphite alloying
• green synthesis
• natural complexing agent

Acknowledgements

The authors wish to express gratitude for the financial support provided by The National University of Malaysia via the DIP-2021-026 research grant. The authors would also like to express their sincere appreciation to the Researchers Supporting Project number (RSPD2024R579) at King Saud University, Riyadh, Saudi Arabia. 

Disclosure statement

No potential conflict of interest was reported by the author(s).