MOF-Assisted Ni-Modified BiOCl Heterojunctions for Coupled Electrochemical Sensing and Photocatalytic Degradation of Ciprofloxacin

Abstract Antibiotic residues are emerging pollutants that severely threaten both environmental safety and human health, demanding advanced catalytic solutions. This study reports a Z-scheme Ni–BiOCl@ZIF-67 (NBZ) heterostructure synthesized via a solvothermal route. By coupling nickel-doped BiOCl with a ZIF-67 metal–organic framework (MOF), the composite effectively addresses the inherent limitations of individual components, such as wide band gaps and rapid charge carrier recombination. The synergistic interaction between the conductive MOF and the doped semiconductor facilitates rapid electron transfer and shows a high sensitivity (0.0183 μA nM–1), an ultralow detection limit (0.90 nM), and an extensive linear dynamic range (10–100 nM), highlighting its strong potential for trace-level detection. Moreover, the incorporation of Ni2+ ions into the BiOCl lattice improves visible-light absorption and facilitates charge separation, while coupling with ZIF-67 enables efficient spatial separation of charge carriers via a direct Z-scheme mechanism. This tailored heterostructure not only extends the visible-light absorption range but also enhances photocatalytic efficiency for the degradation of ciprofloxacin (CIP) (90.05%) under solar-simulated conditions. These findings highlight the potential of the NBZ catalyst as a highly efficient, rapid, and environmentally sustainable platform for wastewater purification, particularly in addressing pollutants from textile and pharmaceutical industries.