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

• The α and h phases, along with hexagonal-type rod-like morphology and the point of zero charge, are identified in the MoO₃ NPs synthesized using Eucalyptus leaf extract. • The effectiveness of antibacterial and antioxidant activities of α and h phase-MoO 3 NPs is evaluated. • The biogenically synthesized α and h-MoO₃ NPs demonstrated photocatalytic activity against RhB and BB dyes, achieving degradation rates of 99.08% and 96.95%, respectively, at pH levels of 5.8 and 3.7. 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 (MoO 3 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 MoO 3 NPs . The FTIR analysis revealed the functional group characteristics of MoO 3 NPs. By the influence of Eucalyptus extract mediation, FE-SEM images showed the hexagonal shape of MoO 3 NPs with well-organized 2D rod-like structures mediated by the Eucalyptus extract. The h-MoO 3 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 MoO 3 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 MoO 3 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 MoO 3 nanocrystalline rods demonstrates excellent catalytic performance and introduces a novel framework for advancing photocatalyst applications.