Efficient photocatalytic bactericidal performance of green-synthesised TiO₂/reduced graphene oxide using banana peel...

In this study, the fabrication of titanium dioxide/reduced graphene oxide (TiO₂/rGO) utilising banana peel extracts (Musa paradisiaca L.) as a reducing agent for the photoinactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was explored. The GO synthesis was conducted using a modified Tour method, whereas the production of rGO involved banana peel extracts through a reflux method. The integration of TiO₂ into rGO was achieved via a hydrothermal process. The successful synthesis of TiO₂/rGO was verified through various analytical techniques, including X-ray diffraction (XRD), gas sorption analysis (GSA), Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), scanning electron microscope-energy dispersive X-ray (SEM-EDX) and transmission electron microscopy (TEM) analyses. The results indicated that the hydrothermal-assisted green synthesis effectively produced TiO₂/rGO with a particle size of 60.5 nm. Compared with pure TiO₂, TiO₂/rGO demonstrated a reduced crystallite size (88.505 nm) and an enhanced surface area (22.664 m²/g). Moreover, TiO₂/rGO featured a low direct bandgap energy (3.052 eV), leading to elevated electrical conductivity and superior photoconductivity. To evaluate the biological efficacy of TiO₂/rGO, photoinactivation experiments targeting E. coli and S. aureus were conducted using the disc method. Sunlight irradiation emerged as the most effective catalyst, achieving optimal inactivation results within 6 and 4 h.