Ternary Metal Chalcogenide Heterostructure (AgInS₂–TiO₂) Nanocomposites for Visible Light Photocatalytic Applications

Hybrid nanoarchitectures of AgInS₂ and TiO₂ photocatalysts were prepared by using a modified sol-gel method. The experimental results reveal that these nanocomposites display enhanced visible light absorption and effective charge carrier separation compared to their pristine parent samples (AgInS₂ or TiO₂). 0.5 wt % AgInS₂ loading was found to be the optimum concentration for photocatalytic applications. More than 95% of doxycycline degradation was achieved within 180 min of solar light illumination. Similarly, the dopant concentrations at lower values (<2 wt %) exhibited 300 times higher H₂ generation rate under visible light irradiation compared to AgInS₂ and TiO₂. The microbial strains (Escherichia coli and Staphylococcus aureus) exhibited a 99.999% reduction within half an hour of simulated solar light illumination. The computational investigation was employed to understand the structural, electronic, and the dielectric properties of AgInS₂ and TiO₂ composites. The improved photocatalytic results are explained as a result of the decreased rate of exciton recombination. The current investigation opens up new insights into the use of novel ternary heterostructure nanocomposites for improved visible light activity.