Construction of S-scheme BiOCl/CdS composite for enhanced photocatalytic degradation of antibiotic

Developing semiconductor-based photocatalytic systems with wide spectral response and effective charge separation is critical to rapidly and efficiently remove antibiotics residues in water. Herein, S-scheme BiOCl/CdS nanocomposites have been successfully designed and synthesized by decorating CdS nanoparticles on the two-dimensional BiOCl nanosheets through a simple hydrothermal method. The composition, microstructure and optical properties of the prepared samples were thoroughly investigated. Tetracycline hydrochloride (TC-HCl) was used as the model pollutant to estimate the photocatalytic properties of BiOCl/CdS catalysts. All the obtained BiOCl/CdS nanocomposites showed enhanced photocatalytic removal of TC-HCl. Especially, the optimal sample showed the highest photodegradation rate, which was 2.94 and 4.73 times that of bare CdS and BiOCl, respectively. The improved degradation of TC-HCl for BiOCl/CdS photocatalysts was ascribed to the increased light absorption as well as the boosted separation and transfer of carriers. Based on the results of active group capture experiment, transient photocurrent, electrochemical impedance spectroscopy and band structure, the S-scheme charge transfer mechanism for TC-HCl degradation in this BiOCl/CdS photocatalytic system was also discussed.