Metal–Organic Framework-Templated Synthesis of In₂S₃/CoS_x Nanocages for Photocatalytic Removal of Antibiotics

Rational design of a hierarchical core–shell structured photocatalyst is crucial for enhancing the separation and transport efficiency of photogenerated carriers, thereby improving the photocatalytic degradation efficiency. In this study, hollow polyhedral CoSx was first synthesized by utilizing dodecahedral Co-based metal–organic framework (ZIF-67) as a Co source and template, followed by introducing In and S species to fabricate hierarchical core–shell In2S3/CoSx composites. The resulting In2S3/CoSx porous hollow heterostructured composites exhibited an accelerated interfacial carrier transfer ratio and enhanced photocatalytic removal performance of tetracycline hydrochloride (TCH). Among them, the optimized sample In2S3/CoSx-2 (CoIS-2) demonstrated the highest TCH removal rate of 0.0324 min–1, which was 22.8 times higher than that of pristine CoSx and 5.7 times higher than that of pure In2S3, respectively. Moreover, its apparent quantum efficiency reached 4.66% at 420 nm. Electron spin resonance analysis and active substance capture experiments confirmed that superoxide radical (•O2–) played a predominant role in the reaction system. Furthermore, we investigated the dynamics of photoinduced carriers through a series of photoelectric tests combined with density functional theory calculations. This study provides valuable insights into controllable construction of metal–organic framework-based materials with high photocatalytic degradation efficiency and stability.