Insights into the enhanced photocatalytic and antioxidant properties of novel biogenically synthesised β-In2S3 quantum dots

Abstract

ABSTRACT In the field of nanoscience and nanobiotechnology, the use of plant extracts in synthesising metal sulphide nanoparticles has lately come to light as an intriguing issue with several benefits over traditional physicochemical methods. Herein, bio-mediated novel β-In2S3 quantum dots were fabricated using Camellia sinensis var. assamica (tea) leaf extract as a stabilising and capping agent through a facile solvothermal technique to evaluate the photocatalytic and antioxidant characteristics. The prepared green β-In2S3 quantum dots (g-β-In2S3), having a bandgap of 2.0 eV, were employed for the degradation of three major categories of dyes Xanthane (Rhodamine B), Triphenylmethane (Malachite Green), and Azo (Biebrich Scarlet). It also showed excellent antioxidant properties compared to standard ascorbic acid and pure chemically synthesised β-In2S3. The g-β-In2S3 quantum dots were characterised for their crystal structure, morphology, surface functional groups, charge recombination delay, and chemical composition using XRD, PL, FTIR, UV-DRS, SEM, TEM, and XPS analyses. The fabricated material showed high crystallinity of 77.17%, a particle size of 6.97 nm, and spherical morphology. The greenly synthesised β-In2S3 displayed enhanced photocatalytic performance, indicating that bio-synthesis can be a superb method to create flexible and environmentally friendly goods. About 75.28 ± 1.69%, 72.31 ± 1.43%, and 62.21 ± 1.14% for Rhodamine B, Malachite Green, and Biebrich Scarlet could be degraded within 60 min of visible light irradiation via β-In2S3/H2O2 system. The kinetics and the mechanism of the degradation of dyes by g-β-In2S3 are also discussed. This work highlighted the potential of g-β-In2S3 quantum dots for enhanced visible light, advanced oxidation process-assisted degradation of dyes, and outstanding antioxidant properties.