ROLE OF DEFECTS AND CRYSTALLITE SIZE OPTIMIZATION IN ENHANCING THE CATALYTIC ACTIVITY OF Zn-DOPED MoO3
Zn-doped MoO₃ nano-particles were synthesised by citric acid-assisted sol-gel method with doping concentrationsof 2%, 4%, 6%, 8%, and 10%, with an objective to enhance their structural and biological functionalities. Theorthorhombic α-MoO₃ phase in all samples, with a size ranging from 45.2 nm (pure MoO3) to 27.6 nmat 10%Zndoping, shows significant lattice strain and defect formation during X-ray diffraction (XRD) analysis. FTIRspectraexhibited characteristic Mo-O stretching vibrations at 993 and 870 cm-1 , with minor red shifts upon doping. Antibacterial activity increased with both doping level and concentration. The 10% Zn-MoO3 at 10 mg mL-1 displayed the highest zones of inhibition-25 mm (Bacillus), 20 mm (Pseudomonas), 19 mm (S. aureus), and 16mm(E. coli). Antioxidant assays revealed dose-dependent radical scavenging, with 10% Zn-MoO3 achieving 26.97%inhibition at 1000 μg mL -1 , while ascorbic acid reached 97.56% under the same conditions. These findings confirmthat Zn doping significantly modifies the structural framework of MoO3, creating surface defects and oxygenvacancies that contribute to enhanced antimicrobial and antioxidant activity, positioning these nanomaterials aspromising agents for biomedical and catalytic applications.
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