Biogenic fabrication of α-h Phase 2D-MoO3 nanomaterials: Comprehensive analysis of physicochemical and impedance properties for biological and photocatalytic applications

The design of high aspect ratio nanomaterials for environmental remedies is gaining attention, mainly through eco-friendly approaches. This study presents the first-ever report on the green preparation of molybdenum oxide nanoparticles (MoO₃ NPs) using a leaf extract derived from Eucalyptus. XRD and Rietveld refinement analysis confirmed the effect of calcination temperature in obtaining the α- and h- phases of MoO₃ NPs. The FTIR analysis revealed the functional group characteristics of MoO₃ NPs. By the influence of Eucalyptus extract mediation, FE-SEM images showed the hexagonal shape of MoO₃ NPs with well-organized 2D rod-like structures mediated by the Eucalyptus extract. The h-MoO₃ nanocrystalline materials with a higher concentration (100 mg/µL) demonstrated exceptional antioxidant and antibacterial characteristics against multi-drug-resistant bacteria, specifically S. aureus and E. coli. The photocatalytic activity for the dye degradation process was investigated with measurement of MoO₃ NPs point-of-zero charges against different pH (1.8, 3.8, and 5.8) and (3.7, 5.7, and 7.7) of Rhodamine B and Brilliant Blue dye solution. The precise point of zero-charge of MoO₃ NPs degraded 99.08% of Rhodamine B dye within 90 min, with a 4.98 × 10⁻² min⁻¹ degradation rate. The cost-effective and environmentally friendly method for the production of 2D MoO₃ nanocrystalline rods demonstrates excellent catalytic performance and introduces a novel framework for advancing photocatalyst applications.