Functional development and enhanced photocatalytic efficiency of GO-supported SnO2 by optimizing composition

Tin oxide (SnO2) nanoparticles were synthesized followed by the preparation of SnO2–graphene oxide (GO) composites in different proportion ratios by a facile two-step hydrothermal method. Obtained nanomaterials were intensively evaluated employing various analyzing techniques. X-ray diffraction (XRD) patterns confirmed the formation of SnO2 in the tetragonal rutile phase, with decreasing crystallite size (10.35 to 2.78) observed as GO content increased in the nanocomposites. Fourier transform infrared (FTIR) spectroscopy revealed the presence of Sn–O and Sn–O–Sn bonding around 636 cm− 1, with broadened peaks upon GO addition indicative of strong interactions between SnO2 and GO. Field-emission scanning electron microscopy (FESEM) & Transmission electron microscopy (TEM) demonstrated the average particle size of SnO2 is 20–60 nm and its uniform distribution with reduced aggregation when supported on GO sheets. Energy-dispersive X-ray spectroscopy (EDS) analyses confirmed the quantification of elemental composition in pure SnO2 and (%Sn:79.36–58.46, %O:20.64–20.96, %C:7.17–20.58) composites with GO. UV-Visible spectroscopy showed a notable reduction in the bandgap from 3.80 eV to 1.98 eV for the SnO2-GO composites than SnO2 by enhancing visible light absorption. Photocatalytic degradation studies highlighted the superior photocatalytic efficiency (99%) of the nanocomposites, achieving highly efficient dye degradation under UV-visible light irradiation. Raman spectroscopy revealed A1g, B2g, and Eg vibrational modes in SnO2, as well as S1 and S2 peaks associated with oxygen vacancies. In the SnO2–GO (1:1) nanocomposite, prominent D and G bands were observed at 1347 cm− 1 and 1615 cm− 1, respectively, with an ID /IG ratio of 1.17, indicating a high level of defects. These structural defects and oxygen vacancies along with charge transfer mechanism confirmed from Photoluminescence (PL) analysis conducted on SnO₂, GO and SnO₂-GO nanocomposites play a major role in enhancing photocatalytic degradation. Electrical conductivity measurements indicated improvement (238.99 S/m for SnO2 to 14598.32 S/m for SnO2-GO 1:1) with addition of graphene oxide. These findings suggest that SnO2–GO composites are promising materials for advanced functional applications and environmental remediation through photocatalytic degradation.