Unveiling the photocatalytic activities of morphology-controlled ZrO2, BaO, and Y2O3 nanoparticles using Eucalyptus leaf extract

This study investigates the synthesis of transition metal oxide nanoparticles, including Zirconium oxide (ZrO2),
Barium oxide (BaO), and Yttrium oxide (Y2O3), using Eucalyptus leaf extract as a green reducing agent through a
sonication-assisted approach. The nanoparticles were thoroughly characterized for their crystalline structure,
functional groups, morphology, and elemental composition. The results confirmed the successful formation of
distinct metal oxide bonds and unique morphological features: ZrO2 exhibited semi-spherical shapes, BaO
showed monodisperse spherical morphology, and Y2O3 displayed a flaky non-spherical structure. The photo�catalytic activity of the nanoparticles was evaluated for the degradation of Brilliant Blue (BB) and Rhodamine B
(RhB) dyes. Among the samples, BaO nanoparticles achieved the highest degradation efficiency, reaching up to
99 % for both dyes under natural sunlight. Antibacterial studies revealed significant activity, with BaO exhibiting
18 mm and 21 mm inhibition zones against E. coli and S. aureus. Real-time turbidimetric growth inhibition tests
further demonstrated BaO’s superior performance, with growth inhibition rates of 81.4 % and 88.6 % against
E. coli and S. aureus. Additionally, antioxidant activity assessed through the DPPH assay indicated that BaO
nanoparticles exhibited the highest radical scavenging ability, surpassing ZrO2 and Y2O3. These findings un�derscore the multifunctional capabilities of BaO nanoparticles, particularly in environmental remediation ap�plications such as dye degradation, antibacterial treatments, and antioxidant activity, highlighting their potential
for sustainable and eco-friendly solutions to pressing biological and ecological challenges.