Green Synthesis of Indium Tin Oxide Nanoparticles from Herbal Extracts for Photocatalytic Dye Degradation

Abstract

Increased emission of harmful and non-biodegradable dyes from industries poses threats to living organisms, thus the need for sustainable effluent treatment methods. This study embarked on a green approach to synthesize indium tin oxide (ITO) nanoparticles applying herbal extracts of the leaves to act as bio-reducing and stabilizing agents. This bio-assisted synthesis discourages the utilization of chemicals that could be toxic. The ITO nanoparticles synthesized showed a cubic bixbyite crystalline structures having been successfully incorporated Sn⁴⁺ ions the lattice In₂O₃, confirmed by XRD analysis. TEM revealed nanoscale and quasi-spherical components with some agglomeration attributed of surface interactions by the phytochemical. FTIR analysis indicated retention of bio-organic functional groups in the regions of 3200 - 3500 cm-1 corresponding to the O-H stretching vibrations of phenolic compounds and alcohol groups. At 1630-1650 cm-1 have C=O stretching vibrations of amide and carbonyl groups while peaks at 1380-1450 cm-1 are aromatic C-C stretching and C-N vibrations that partially interacted with the nanoparticle surface thus contributed to an enhanced stability on the surface and interfacial transfer of charge. From the Optical studies there was an improved absorption of light and a modification of band gap of 3.83 eV, where PL analysis suggested a suppression in the recombination of electron–hole. The performance of photocatalytic activity by the green-synthesized indium tin oxide nanoparticles was determined utilizing MB dye model by light irradiation. These nanoparticles illustrated efficiency in dye degradation by pseudo-first-order kinetics, showing enhanced performance attribution of increased SA, oxygen vacancies, Sn doping, and bio-induced defect surfaces. The proposed mechanism involved the production of reactive oxygen, OH and superoxide species, resulting in the mineralization of dye components. Overall, this study highlighted the potentiality in extract-mediated green synthesis as an alternative path in production efficiency of ITO photo-catalysts and by extension their applications other than just conventionally optoelectronic uses for the environmentally friendly effluent removal technologies.