Tuning the core-shell ratio in nanostructured CuS@In2S3 photocatalyst for efficient dye degradation

This work reports on a microwave-assisted solvothermal synthesis of CuS@In₂S₃ core-shell hybridized nanoparticles (Hy-NPs) at different weight ratios (wt%) of CuS to tune the heterojunction optoelectronic properties and evaluate the application for photocatalytic degradation of organic dyes. The photodegradation performance in terms of the efficiency and reaction kinetics shows that the 10 wt% CuS Hy-NPs presents the highest photoactivity in the degradation of two dye species, methylene blue (MB) and methyl orange (MO) when compared to 5 wt% CuS, 15% CuS Hy-NPs samples as well as the pristine CuS or In₂S₃ NPs. The structural and morphological studies combining the optical bandgap analysis suggest that the CuS amount used in the synthesis step plays an important role to forming the efficient heterojunction interfaces for charge carrier separation to inhibit the recombination of excited electron and hole pairs and the resultant apparent optical bandgap of the Hy-NPs. The 10 wt% CuS@In₂S₃ core-shell Hy-NPs demonstrate a lower optical band for a wide range visible light absorption and higher photocatalytic activity than that of the CuS NPs, In₂S₃ NPs, and the 5 wt% CuS, or 15 wt% CuS Hy-NPs. The findings in this work may offer an alternative simple and effective approach to designing and synthesizing metal chalcogenide heterojunctions for improving photocatalytic activity.