Synthesis of Aluminum Oxide (Al₂O₃) Nanoparticles Decorated With Polymeric Carbon (Al₂O₃/AC) Nanocomposites for High Specific Capacitance Value

ABSTRACT Aluminum oxide nanoparticles/activated carbon (Al 2 O 3 NPs/AC) nanocomposite were synthesized using an optimized sol–gel synthesis method. Various characterization techniques, including x‐ray, field emission scanning electron microscopy (FE‐SEM), Fourier transform infrared (FTIR), UV–visible spectroscopy and cyclic voltammetry, were employed electrochemical properties of the prepared samples. X‐ray diffraction (XRD) analysis revealed higher crystal plane intensities in Al 2 O 3 NPs compared to Al 2 O 3 /AC nanocomposites. The average crystallite size was determined to be 32 nm for Al 2 O 3 NPs and 20 nm for Al 2 O 3 /AC nanocomposites. FE‐SEM showcased the agglomeration of Al 2 O 3 NPs, while the composite exhibited agglomerated Al 2 O 3 NPs embedded in Al 2 O 3 /AC nanocomposites. It was found that the band gaps of Al 2 O 3 /AC nanocomposite and Al 2 O 3 NPs were 5.5 and 5.6 eV, respectively. Electrochemical analysis through cyclic voltammetry demonstrated that the specific capacitance of Al 2 O 3 /AC nanocomposites was six times higher than Al 2 O 3 NPs. This comprehensive investigation provides valuable insights into the enhanced electrochemical performance of the Al 2 O 3 /AC nanocomposites, suggesting its potential application in energy storage devices.