Structural Characterization of SnO2-rGO Heterogeneous Photocatalyst with Enhanced Antimicrobial Properties

Abstract

The integration of SnO2 nanoparticles (NPs) with reduced graphene oxide (rGO) offers a unique approach for antimicrobial applications and photocatalytic degradation of organic contaminants. In this study, binary heteronanostructures were synthesized via a hydrothermal method using 2 and 4 wt% rGO. Optical properties, crystallinity, IR spectra, and surface morphology, along with elemental configuration, were characterized through DRS, XRD, FTIR, SEM, and EDX techniques. A progressive reduction in the bandgap (Eg) was observed for SnO2-rGO-A (2 wt%) and SnO2-rGO-B (4 wt%) BNCs as compared to pure SnO2 NPs, i.e., from 3.6 to 3.30 eV and then to 3.25 eV, respectively. The narrow band gap near UV region, suggested enhanced light-harvesting capacity. Photocatalytic efficiency was evaluated under visible light in a photocatalytic reactor using a 200 W Xe lamp as the irradiation source, with methylene blue (MB) dye as the target pollutant. SnO2-rGO-B BNCs showed the highest photodegradation efficiency (97%), followed by SnO2-rGO-A (91%) and SnO2 NPs (64%). Antibacterial evaluation against Staphylococcus aureus revealed highest zone of inhibition (ZOI) at a 10 mg/L sample concentration, with SnO2-rGO-B exhibiting the most potent activity. The results show that rGO improves photocatalytic and antibacterial performance, making the composite suitable for environmental and antimicrobial applications.