One-pot biogenic synthesis of C. limon/TiO2 with dual applications as an advance photocatalyst and antimicrobial agent

Abstract

The present study portrays a facile, cost-effective, and environmentally benign way for the preparation of TiO2 nanoparticles utilizing C. limon extract, which possesses phytochemicals as reducing and stabilizing agents. Structural characterization by XRD reveals that C. limon/TiO2 NPs exhibit anatase-type tetragonal crystallinity. An average crystallite-size is calculated using Debye Scherrer's method (3.79 nm), Williamson–Hall plot (3.60 nm), and Modified Debye Scherrer plot (3.68 nm), which are very closely intercorrelated. The absorption peak at 274 nm (UV–visible spectrum) corresponds to the bandgap (Eg) value of 3.8 eV. The existence of different phytochemicals containing organic groups like N–H, C=O, and O–H, has been elucidated from FTIR along with Ti–O bond stretching at wavenumber 780 cm−1. Micro-structural investigations of TiO2 NPs using FESEM and TEM display different geometrical configurations involving spherical, pentagonal, hexagonal, heptagonal and capsule-like structures. BET and BJH analysis show mesoporous characteristics of synthesized nanoparticles with specific surface-area (97.6 m2 g−1), pore-volume (0.018322 cm3 g−1), and mean pore-diameter (∼7.5 nm) values. In adsorption studies, the influence of reaction parameters, i.e., catalyst dosage and contact-time, for removal of Reactive Green dye is explored along with Langmuir and Freundlich models. The highest adsorption capability is ∼219 mg g−1 for green dye. TiO2 displays an excellent photocatalytic efficiency of ∼96% towards the degradation of reactive green dye within 180 min and excellent reusable performance. C. limon/TiO2 is found to have an outstanding performance with a quantum yield value of 4.68 × 10−5 molecules photon−1 for Reactive Green dye degradation. Additionally, synthesized nanoparticles have exhibited antimicrobial activity against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Pseudomonas aeruginosa (P. aeruginosa) bacteria.