Role of rGO reinforced Er-WO3 in biological, photocatalytic, luminescence and forensic applications

Abstract

The advancement of multifunctional heterostructured nanocomposites has garnered significant attention due to their promising applications. In this study, multifunctional WO₃, Erbium-doped WO₃ (Er-WO₃), and Er-WO₃/reduced graphene oxide (Er-WO₃/rGO) composites were synthesized using the solution combustion method, with Jamaican cherry (Muntingia calabura) fruit juice serving as a bio-template. The structural, optical, and morphological properties of the synthesized nanomaterials were characterized through Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), and ultraviolet–visible diffuse reflectance spectroscopy (UV-DRS), Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The photocatalytic efficiency of the materials in dye degradation was investigated, revealing that Er-WO₃/rGO exhibited superior performance compared to its undoped and doped counterparts, achieving a 94.9 ± 4.75 % degradation of Methylene Blue (MB) dye within 150 min. The photoluminescence spectra of Er-WO₃/rGO demonstrated efficient charge carrier separation. Furthermore, Er-WO₃/rGO facilitated the visualization of latent fingerprints, displaying well-defined ridge patterns with high resolution. Antibacterial activity assessments against Escherichia coli and Staphylococcus aureus revealed inhibition zones of 13.66 ± 1.15 mm and 14.33 ± 0.57 mm, respectively, following 12 h of incubation. Additionally, Er-WO₃ and Er-WO₃/rGO exhibited antioxidant activity against DPPH (2, 2-diphenyl-1-picrylhydrazyl) free radicals, with IC₅₀ values of 4899 μg/mL and 4000 μg/mL, respectively. The incorporation of Erbium (Er) into the WO₃ crystal lattice led to a reduction in crystallite size and bandgap energy, enhancing its functional properties. Meanwhile, the inclusion of rGO contributed to increased porosity and electrical conductivity, further promoting charge separation within the photocatalyst. Overall, this study introduces a novel approach for the development of multifunctional Er-WO₃/rGO nanohybrids, highlighting their potential for applications in photoluminescence, latent fingerprint detection, photocatalytic dye degradation, antibacterial activity, and antioxidant functionality.