Hierarchical columnar ZnIn₂S₄/BiVO₄ Z-scheme heterojunctions with carrier highway boost photocatalytic mineralization of antibiotics

How to achieve high-speed directional migration and separation of photogenerated carriers at heterointerfaces is still an important factor restricting efficient photocatalytic reactions. Herein, hierarchical columnar ZnIn₂S₄/BiVO₄ (ZIS/BVO) Z-scheme composite with photogenerated carriers highway in heterogeneous interface are designed by an in situ technique. Ultrathin ZIS nanosheets are uniformly grown upright on the surface of mulberry-like BVO pillars. The confined built-in electric field and Z-scheme heterojunction in ZIS/BVO are verified in detailed by synchronous illumination X-ray photoelectron spectroscopy, theoretical calculation, electron spin resonance spectroscopy, and high-resolution TEM. The photogenerated electrons in the conduction band (CB) of BVO migrate to the valence band (VB) of ZIS through heterojunction, whereas holes in the VB of BVO and electrons in the CB of ZIS maintain the original high redox capability. These holes and electrons with high redox capability react with H₂O and O₂ to generate more •OH and •O₂⁻, respectively, achieving enhanced photocatalytic mineralization antibiotic properties. The mineralization rate of antibiotics in the optimized ZIS/BVO material are 4.4 and 1.8 times higher than that of pure BVO and ZIS, respectively.