Investigating the catalytic and antibacterial behavior of cesium-doped MoO3 nanostructures against methylene blue dye and MDR E. coli with DFT analysis

Water pollution, exacerbated by inadequate water management practices, has compromised the effectiveness of traditional water treatment technologies. The integration of metal oxide-based nanomaterials in treatment systems has the potential to revolutionize the field of wastewater treatment, providing a sustainable and efficient solution to the growing global water crisis. This study focused on the fabrication of hexagonal cesium (Cs) doped MoO₃ nanostructures (NSs) for their potential use as catalytic and antibacterial agents. Various structural, optical, and morphological analysis was conducted to examine these NSs. The UV–Vis spectroscopy results showed that as Cs concentration increased, the band gap energies of MoO₃ decreased from 3.5 eV to 3.0 eV. The field emission scanning electron microscopy (FESEM) investigation revealed the plate-like structural morphology of MoO₃ formed by overlapping one layer onto another. Cs doping effectively inhibited the recombination of photo-generated charge carriers, resulting in a significant reduction in PL peak intensity for Cs-doped MoO₃ compared to MoO₃. The prepared NS-reduced methylene blue dye in the absence of light under different pH conditions, reaching 86.8% with 2% Cs-doped MoO₃. Density functional theory (DFT), utilizing the Heyd-Scuseria-Ernzerhof hybrid (HSE06) method, was employed to model and compute the interactions between methylene blue (MB) and Cs-doped MoO₃ during MB adsorption. Bactericidal experiments on multidrug-resistant Escherichia coli showed that the NSs had remarkable antibacterial action, generating an inhibition zone of 9.15 mm at higher doses using 6% Cs-doped MoO₃. Consequently, these findings offer potential significance for research in developing and implementing wastewater disinfection systems.