Microwave-assisted synthesis and functionalization of nanocrystalline molybdenum trioxide for enhanced antimicrobial and photocatalytic activity

Abstract

Molybdenum Trioxide nanoparticles (MoO3) were synthesized using ammonium heptamolybdate tetrahydrate [(NH4)6Mo7O24·4H2O] as the primary precursor via the microwave-assisted method and subsequently functionalized with surfactants such as Cetyltrimethylammonium bromide (CTAB), Sodium n-dodecyl sulfate (SDS), and Thioglycolic acid (TGA). The characterization involved X-ray diffraction, field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and UV–Visible spectroscopy, revealing hexagonal plate-like morphology, UV absorbance at 202–216 nm with a band gap of 4.2 eV, and a crystalline structure with a 44 nm size calculated by the Scherrer's equation. The synthesized pure (MoO3) and functionalized molybdenum trioxide nanoparticles (FMoO3) were tested for antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Salmonella typhi. Furthermore, MoO3 and FMoO3 also demonstrated enhanced antifungal activity against the fungi Aspergillus niger (Accession No. MZ435922) and Aspergillus fumigatus (Accession No. MZ435863). Photocatalytic experiments demonstrated significant degradation of malachite green dye under UV light irradiation, notably with SDS functionalized MoO3 achieving 98.17 % degradation rate within 20 min, with a linear rate constant of 0.20343 min−1. These findings highlight the potential of MoO3 and FMoO3 nanoparticles as effective antimicrobial agents and their suitability for water purification due to their low toxicity.