Solanum torvum Derived Zirconium Oxide Nanoparticles as Fluorescent Sensors and Photocatalysts

ZrO 2 nanoparticles were biosynthesized using Solanum torvum fruit extract. Their structural and morphological properties were investigated through UV–visible studies, photoluminescence, Fourier transform infra‐red spectroscopy, energy‐dispersive X‐ray analysis, X‐Ray diffraction, X‐ray photoelectron spectroscopy and high‐resolution transmission electron microscopy. O 2− →Zr 4+ transition was confirmed by the peak observed at 222 nm in UV–visible spectrum and the band gap was estimated as 4.46 eV, indicating dielectric nature. Zr─O─Zr bond was confirmed by the bands observed at 738 and 613 cm −1 in FTIR spectroscopy. EDX spectra showed characteristic peaks of oxygen and zirconium. XPS showed binding energies of 182.7 and 184.9 eV, which correspond to spin‐orbit splitting of Zr 3d 5/2 and Zr 3d 3/2 , respectively. The absence of metallic zirconium was confirmed by the absence of peaks at 178.7 and 181.1 eV, which also confirmed that Zr is present in +4 state. The particle size was determined to be 13 and 17 nm using XRD and TEM, respectively. Effective fluorescence sensing of L‐glycine was observed with a detection limit 1.27 × 10 −8 M. Photocatalytic reduction of 2,4‐dinitrophenylhydrazine showed 87.6% conversion and reusability of the catalyst up to five consecutive cycles. Cytotoxicity studies using A549 human lung cancer cell line showed IC 50 value of 225 µg/mL.