Biosynthesis of tin(IV) oxide nanoparticles from leaves extract of C. odorata, A. malaccensis and P. amaryllifolius for methylene blue degradation

This study explores a green biosynthesis approach using extracts from Chromolaena odorata, Aquilaria malaccensis and Pandanus amaryllifolius leaves, which are rich in flavonoids, as reducing and capping agents. The approach exhibits novelty by being both rapid in production and effective in the photodegradation of methylene blue. The extracts were mixed with a tin chloride solution at ambient conditions, followed by calcination. Characterization through XRD and FTIR confirmed that the SnO2 NPs exhibit a rutile phase with a tetragonal structure, with Sn-O and Sn-OH stretching vibrations identified around 900 and 1100 cm-1. HRTEM analyses showed spherical SnO2 NPs with sizes of 7.68, 9.41 and 7.63 nm. UV-DRS tests revealed energy band gaps of 3.00, 3.12 and 2.79 eV, sufficient to absorb photons for photocatalytic applications. Lattice spacings of 0.3311, 0.3296 and 0.3300 nm, coupled with homogeneous distribution and electronegative charge, further supported their effectiveness. Photocatalytic tests using methylene blue dye under UV irradiation demonstrated high degradation efficiencies of 97%, 94%, and 80% at neutral pH, outperforming both acidic and alkaline conditions. This suggests that, when compared to the other two plant materials, C. odorata has demonstrated the greatest significance as a biotemplate for SnO2 NPs photocatalyst. Furthermore, SnO2 NPs exhibited high stability and reusability for up to five cycles. In summary, this biosynthesis method for SnO2 NPs is straightforward, cost-effective, and environmentally friendly, producing highly stable and reusable photocatalysts.