Efficient photocatalytic bactericidal performance of green-synthesised TiO2/reduced graphene oxide using banana peel extracts
Maisari Utami, Tong Woei Yenn, Mir Waqas Alam, Balasubramani Ravindran, Husniati, Indra Purnama, Salmahaminati, Habibi Hidayat, Faustine Naomi Dhetaya, Siva Nur Salsabilla
Abstract
In this study, the fabrication of titanium dioxide/reduced graphene oxide (TiO 2 /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 TiO 2 into rGO was achieved via a hydrothermal process. The successful synthesis of TiO 2 /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 TiO 2 /rGO with a particle size of 60.5 nm. Compared with pure TiO 2 , TiO 2 /rGO demonstrated a reduced crystallite size (88.505 nm) and an enhanced surface area (22.664 m 2 /g). Moreover, TiO 2 /rGO featured a low direct bandgap energy (3.052 eV), leading to elevated electrical conductivity and superior photoconductivity. To evaluate the biological efficacy of TiO 2 /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.