Bi2O3-Doped WO3 Nanoparticles Decorated on rGO Sheets: Simple Synthesis, Characterization, Photocatalytic Performance, and Selective Cytotoxicity toward Human Cancer Cells

Graphene derivativesand metal oxide-based nanocomposites (NCs)are being studied for their diverse applications including gas sensing,environmental remediation, and biomedicine. The aim of the presentwork was to evaluate the effect of rGO and Bi2O3 integration on photocatalytic and anticancer efficacy. A novel Bi2O3-WO3/rGO NCs was successfully preparedvia the precipitation method. X-ray crystallography (XRD) data confirmedthe crystallographic structure and the phase composition of the preparedsamples. Scanning electron microscopy (SEM) and transmission electronmicroscopy (TEM) analysis confirmed the loading of Bi2O3-doped WO3 NPs on rGO sheets. Energy-dispersiveX-ray (EDX) results confirmed that all elements of carbon (C), oxygen(O), tungsten (W), and bismuth (Bi) were present in Bi2O3-WO3/rGO NCs. The oxidation state and presenceof elemental compositions in Bi2O3-WO3/rGO NCs were verified by the X-ray photoelectron spectroscopy (XPS)study. Raman spectra indicate a reduction in carbon-oxygenfunctional groups and an increase in the graphitic carbon percentageof the Bi2O3-WO3/rGO NCs. The functionalgroup present in the prepared samples was examined by Fourier transforminfrared (FTIR) spectroscopy. UV analysis showed that the band gapenergy of the synthesized samples was slightly decreased with Bi2O3 and rGO doping. Photoluminescence (PL) spectrashowed that the recombination rate of the electron-hole pairdecreased with the dopants. Degradation of RhB dye under UV lightwas employed to evaluate photocatalytic performance. The results showedthat the Bi2O3-WO3/rGO NCs have highphotocatalytic activity with a degradation rate of up to 91%. Cytotoxicitystudies showed that Bi2O3 and rGO addition enhancethe anticancer activity of WO3 against human lung cancercells (A549) and colorectal cancer cells (HCT116). Moreover, Bi2O3-WO3/rGO NCs showed improved biocompatibilityin human umbilical vein endothelial cells (HUVECs) than pure WO3 NPs. The results of this work showed that Bi2O3-doped WO3 particles decorated on rGO sheets displayimproved photocatalytic and anticancer activity. The preliminary datawarrants further research on such NCs for their applications in theenvironment and medicine.

Automated summary

Graphene derivatives and metal oxide-based nanocomposites (NCs) are investigated for various applications. This study demonstrates that the integration of rGO and Bi2O3 enhances photocatalytic and anticancer efficacy, and the prepared Bi2O3-WO3/rGO NCs exhibit improved activity.