Green Synthesis and Characterization of Tin (IV) Oxide Nanoparticles from Fresh and Dried Senna alata Leaf Extract

Abstract

Despite the growing interest in plant-mediated nanoparticle synthesis, limited research has examined how the condition of plant material (fresh or dried) has affected the efficiency and quality of synthesized nanoparticles. This study reports the green synthesis of tin (IV) oxide (SnO?) nanoparticles using aqueous extracts from fresh and dried Senna alata leaf as reducing, stabilizing, and capping agents, with 1.0 M Tin (II) chloride dihydrate (SnCl?·2H?O) as the precursor. Structural, morphological, optical, and thermal properties of the synthesized nanoparticles were investigated. XRD analysis confirmed the formation of crystalline tetragonal rutile-phase SnO?, with average crystallite sizes of 3.7 nm for fresh-leaf extract and 8.19 nm for dried-leaf extract. FTIR spectra revealed stronger and more distinct functional groups (O–H, C–H, C–O, and NO??) in nanoparticles derived from fresh extracts. SEM and TEM analyses showed uniformly distributed, spherical nanoparticles with minimal agglomeration and average particle sizes of 9.88 nm (fresh extract) and 9.80 nm (dried extract). EDX analysis confirmed elemental purity with dominant Sn and O signals and complete removal of chlorine residues. Optical studies demonstrated that fresh-leaf-derived nanoparticles exhibited higher absorbance, lower transmittance, and a narrower band gap (3.21 eV) compared to the dried-leaf counterpart (3.58 eV). Thermal conductivity results indicated superior heat-transport performance for nanoparticles synthesized from fresh leaves, particularly at lower temperatures. These findings demonstrated that fresh Senna alata leaf extract provides a potential sustainable and efficient route for producing high-quality SnO? nanoparticles with enhanced optical and thermal properties for advanced technological applications.