Bi-metal-organic framework-derived S-scheme InP/CuO-C heterostructure for robust photocatalytic degradation of ciprofloxacin in a microfluidic photoreactor

The presence of antibiotics in the environment raises significant environmental concerns due to their adverse impact on organisms and the potential transmission of drug-resistant genes. Heterostructure photocatalysts have emerged as a promising remedy for this issue. This study introduces an innovative approach that employs an In/ Cu-organic framework (bimetallic-MOF) as a sacrificial precursor for crafting a carbon-supported InP/CuO heterostructure with adjustable band-matching properties. Through comprehensive analyses encompassing structural, morphological, optical, electrochemical, and density functional theory calculations, compelling evidence is presented for the cubic carbon layer housing zinc-blende InP and monoclinic CuO. Furthermore, the existence of an S-scheme charges transfer pathway between InP and CuO is strongly substantiated, significantly enhancing spatial charge separation. The engineered InP/CuO S-scheme nanoheterostructure exhibits exceptional performance and stability under visible light exposure within a custom-designed spiral microfluidic photoreactor (SMPR), achieving an impressive 81.70% degradation of ciprofloxacin - a commonly found anti-biotic in wastewater - in just 15 min. The findings from photoelectrochemical and spectroscopic analyses reveal that the InP/CuO S-scheme heterostructure, derived from the bi-MOF, in conjunction with the SMPR, not only exhibits a robust response to visible light, improved carrier mobility, and effective charge separation and transfer, but also enhances mass and photon transfer. Within the S-scheme heterostructure, the process of charge transfer centers on the creation of reactive oxygen species, specifically center dot OH and center dot O2-, on InP and CuO surfaces, correspondingly. These species function as oxidation and reduction photocatalysts, respectively, exerting a pivotal influence in augmenting the overall performance. The findings make substantial contributions towards creating effective and sustainable solutions for mitigating environmental contamination, emphasizing the crucial role of advanced material design and microfluidic reactor engineering in the realm of photocatalysis.