2D/2D P‐Doped G‐C ₃ N ₄ /BiOCl _0.75 I _0.25 S‐Scheme Van der Waals Heterojunction Photocatalysts for Boosting Tetracycline Hydrochloride Degradation

Developing stable and efficient photocatalysts is a promising approach for mitigating water pollution. A major challenge is the high recombination rate of photogenerated carriers, which hampers the efficiency of these photocatalysts. To address this challenge, element doping, morphology regulation, and heterostructure construction are considered effective strategies for improving the efficiency of photogenerated carrier separation. Hence, a 2D/2D S-scheme Van der Waals heterojunction (PCN/BOCI) is successfully synthesized by combining P-doped g-C₃N₄ (PCN) with BiOCl_0.75I_0.25 (BOCI). The optimal 6:4 PCN/BOCI composite achieves a tetracycline hydrochloride (TC) degradation rate that is 2.4 times higher than that of pure PCN and 1.6 times higher than pure BOCI under visible light irradiation. The results suggest that the 2D/2D S-scheme Van der Waals heterojunction by offering more active sites, reduces carrier transport distance, enhances carrier separation efficiency, and improves REDOX ability compared to the individual PCN and BOCI components. Furthermore, a detailed analysis is conducted on the toxicology and biotoxicity of the degradation products to ensure that they do not pose additional environmental or health risks. This work provides a theoretical and experimental basis for the design and development of high-performance S-scheme heterojunction photocatalysts.