Biosynthesis of ZrO₂ nanoparticles from Ficus benghalensis leaf extract for photocatalytic activity

The biosynthesis of metal oxide nanoparticles (NPs) using plant extract is green, rapid, attractive and cost-effective approach. In the present study, we are reporting biosynthesis of ZrO₂ NPs as an efficient photocatalyst by using Ficus benghalensis (F.B.) leaf extract as a capping agent for the first time. To determine its optical, structural and morphological properties, the obtained ZrO₂ NPs were characterized by using UV–Vis, DRS, XRD, FT-IR, HR-TEM, FT-Raman and BET-surface area. XRD pattern confirms that biosynthesized ZrO₂ NPs are crystalline in nature with monoclinic and tetragonal structure. TEM images show that the obtained ZrO₂ NPs has spherical morphology with 15 nm in size which is good agreement with XRD results. A decrease in the band gap of bulk ZrO₂ from 5.3 to 4.9 eV is observed due to the quantum size effect. The as-synthesized ZrO₂ NPs have high specific surface area of 88 m²/g was obtained by BET analysis. The photocatalytic efficiency of ZrO₂ NPs is evaluated for the photodegradation of methylene blue and methyl orange dyes as the target pollutants under UV light irradiation. The different parameters like catalyst loading amount and pH have also been studied. It is observed that photodegradation of methylene blue and methyl orange up to 91 and 69% within 240 min by using ZrO₂ catalyst. Moreover, this green synthesis process provides a valuable alternative to orthodox multistep processes for the preparation of ZrO₂ NPs.