Innovative catalytic approaches in fabricating bimetallic heterostructures for remediation of antibiotic-polluted water: Mechanistic insights and application prospects

The development of photocatalysts with enhanced antibiotic removal efficiency and practical applicability represents a promising avenue. Bimetallic catalysts, as a focal point in photocatalysis research, face challenges in elucidating their operational mechanisms, the absence of straightforward preparation methodologies and comprehensive recycling system when applied to remediation of water bodies. This study innovates by employing an in-situ growth technique to incorporate manganese ferrate nanomaterials onto bismuth oxychloride nanoflowers (MnFe₂O₄@BiOCl), aiming to construct bimetallic active sites for the photocatalytic degradation of cefalexin (CFX) through a heterojunction structure. The incorporation of MnFe₂O₄ significantly boosts the adsorption properties, photoelectric response, and CFX removal efficiency (from 5.03 mg/g to 10.27 mg/g) by BiOCl. XPS analysis reveals that the bimetallic structure facilitates photogenerated electron transfer via Mn-O-Bi coordination, delaying the electron-hole recombination, which then acts upon water or hydroxyl groups (–OH) adsorbed onto the surface, generating a multitude of reactive radicals that enhance the photoelectric performance. The study demonstrates that MnFe₂O₄@BiOCl can continuously photo-catalyze the removal of CFX with a simple and complete recycling strategy, showcasing high recycling efficiency. We posit that bimetallic catalysts prepared via heterojunction structures can achieve efficient CFX antibiotic removal while preserving excellent reusability. The proposed strategy is envisaged to be a promising approach for the photocatalytic removal of antibiotics, offering a sustainable solution for remediation of water.