Construction of Crystalline Red Phosphorus/Fe-MOF Z-Scheme Heterojunctions for Enhanced Photocatalytic Degradation of Tetracycline

Antibiotic contamination, especially from persistent compounds like tetracycline (TC), has emerged as a serious environmental concern due to its resistance to conventional treatment processes. In this study, crystalline red phosphorus nanoribbons (cRP NRs) were integrated with iron-based metal–organic frameworks (MIL-101 and MIL-101-B) via a solvothermal method to construct composite photocatalysts for enhanced TC degradation. The optimized cRP NRs/MIL-101 composite (mass ratio 1:1) exhibited the highest photocatalytic efficiency, achieving 80% TC removal under visible-light irradiation—significantly outperforming both pristine cRP and MIL-101. Structural and optical characterizations confirmed the formation of a Z-scheme heterojunction between cRP NRs and MIL-101, which effectively promoted charge separation, broadened light absorption, and enhanced the generation of reactive oxygen species. Radical scavenging experiments and band structure analysis revealed that ·O₂⁻ and h⁺ played dominant roles in the degradation pathway. The composite also demonstrated good stability and recyclability over multiple cycles. This work provides a rational strategy for designing MOF-based heterostructured photocatalysts for efficient antibiotic removal from wastewater.