Rational Design of PCN/Ce-MOF S-Scheme Heterojunction for Highly Efficient Synergistically Photocatalytic H2 Evolution and Tetracycline Degradation

Catalytic systems that couple pollutant degradation with hydrogen evolution have attracted significant attention due to their potential to simultaneously address environmental and energy issues. In this study, an S-scheme heterojunction composed of lamellar polymeric carbon nitride (PCN) anchored with a rod-like cerium metal-organic framework (Ce-MOF) was successfully synthesized via a facile one-step oxidation method, enabling efficient visible-light-driven photocatalytic hydrogen evolution and simultaneous tetracycline degradation. The optimized PCN/Ce-MOF composite delivers a hydrogen production rate of 495.7 μmol g^-1 h^-1 and achieves a tetracycline removal efficiency of 78%. Such excellent performance is attributed to the charge transfer mechanism of the S-scheme heterojunction in the PCN-Ce-MOF composite during the reaction process, while retaining the intrinsic redox capabilities of both materials. Meanwhile, mechanistic studies reveal that tetracycline can effectively capture holes during its efficient degradation, inhibit electron-hole recombination, and promote proton reduction to generate hydrogen. This investigation provides valuable insights for the rational design of S-scheme heterojunction photocatalysts, aiming to achieve efficient and stable photocatalytic hydrogen production and synergistic degradation of organic pollutants.