Low-temperature synthesis of graphite flakes and carbon-based nanomaterials from banana peels using hydrothermal process for photoelectrochemical water-splitting

Herein, we report the synthesis of carbon nanostructures from banana peels at low hydrothermal temperatures. A one-step hydrothermal method was used, and the desired product was obtained at 220 degrees C using two dispersant solvents (distilled water (S1) and ethanol (S2)). The formation of carbon nanomaterials and graphite flakes has been confirmed through various characterization techniques. The Scanning Electron Microscopy (SEM) analysis shows a graphite flake-like morphology using water as a solvent and a mix-up of graphite flakes and carbon nanoparticles presence using ethanol as a solvent. Two primary elements i-e., carbon (C) and oxygen (O) were observed in the Energy Dispersive X-ray (EDX) analysis. The X-ray Diffraction (XRD) analysis shows the graphitic diffraction peak that confirms the formation of graphite flakes and carbon nanomaterials with good crystallinity. Fourier Transform Infrared (FTIR) analysis reveals the signature of O-H, C-H, C-O, C-O-2, bonds along with C=O and C=C bonds. UV-Visible (UV-Vis) spectroscopy shows absorption at 230 nm for (S2) and 270 nm for (S1) which correspond to the pi-pi* and n-pi* transitions of C=C and C=0, respectively. The photoelectrochemical (PEC) analysis shows that the sample (S2) has a higher photocurrent density and low charge-transfer-resistance than the sample (S1) because of its finer size. The study thus provides a simple pathway for the preparation of carbon-based nanomaterials on a large scale.

Automated summary

The synthesis of carbon nanostructures from banana peels at low hydrothermal temperatures is reported. The study confirms the morphology and composition of the materials using various characterization techniques, and analyzes their properties.