Transition metal-doped SnO and graphene oxide (GO) supported nanocomposites as efficient photocatalysts and antibacterial agents.

In the present work, pristine and transition metal (TM) (W, Ag, Zn)-doped SnO nanocrystals using a facile sol-gel approach were synthesized. The grown products were anchored on graphene oxide (GO) sheets via a simple ultrasonication technique to fabricate binary nanocomposites. The structural, optical, and morphological properties of as-synthesized samples were studied by XRD, FTIR, Raman, EDX, UV-Visible, PL, and FE-SEM. The charge transferability of graphene oxide-based samples was investigated by EIS. The XRD exhibited the TM doping in SnO and the development of GO-based nanocomposite. FTIR data evidenced the existence of the metal-oxygen bonds. Raman spectra presented the optical phonon modes of SnO and the existence of oxygen vacancy defects. FE-SEM images demonstrated the anchoring of particles on the GO sheet, and EDX further approved the existence of desired dopants. The integration of SnO with TM doping remarkably reduced optical bandgap (3.65-3.10 eV), which was further decreased (3.10-2.99 eV) by making composite with GO. The photodegradation results exhibited that GO-based nanocomposites have the higher potential to degrade synthetic dyes (methyl red (MR), and methyl orange (MO) and SnZnO/GO have shown superb photocatalytic performance after 80-min sunlight illumination (99.9% MR and 95.0% MO dyes) with the higher rate constant and superior stability up to 6th cycle against MR dye. The grown samples were tested for bacterial disinfection, and SnZnO/GO sample showed a higher zone of inhibition towards S. aureus and K. pneumoniae bacteria strains. The greater charge transfer rate and lower recombination of charge carriers in GO-based composites were also observed by EIS and PL analysis. Moreover, the present article ascribed that the photocatalytic and antibacterial properties of bare SnO could be improved by TM doping and fabricating their composite with GO.