Efficient solar-driven decontamination of waterborne antibiotics and dyes via 2D/2D/2D heterointerface engineering and S-scheme charge transfer in a Ti3C2 MXene/BiOIO3/g-C3N4 ternary heterostructure

초록

The escalating accumulation of pharmaceutical contaminants and synthetic dyes in water bodies poses a serious threat to environmental sustainability and human health. Herein, we report the rational design and fabrication of a ternary heterostructure composed of graphitic carbon nitride nanosheets (CNS), BiOIO3 nanoplates (BIP), and exfoliated Ti3C2 MXene (TCM) for solar-driven photocatalytic remediation of organic pollutants. Structural and spectroscopic analyses confirmed intimate interfacial integration of the three components into a cohesive 2D/ 2D/2D architecture. Among the prepared catalysts, the optimized TBC-20 composite achieved complete degradation of ciprofloxacin (CIP) within 60 min of solar irradiation, with a mineralization efficiency of 72.4%. It also demonstrated broad applicability by effectively degrading azo (Congo Red) and xanthene (Rhodamine B) dyes, confirming its versatility. Kinetic analysis revealed a degradation rate constant several times higher than those of pristine CNS, BIP, and the binary composite. Importantly, TBC-20 retained more than 96% of its activity after six successive cycles, underscoring its robustness and reusability. Mechanistic studies supported by radical scavenging, ESR, and in situ XPS analyses established an S-scheme charge-transfer pathway that promotes efficient charge separation, suppresses recombination, and preserves strong redox potentials. The synergistic effects of 2D/2D/2D hybridization, enhanced light harvesting, and enlarged surface area collectively enable the outstanding performance. This study establishes an effective interfacial engineering strategy for constructing multifunctional 2D/2D/2D S-scheme heterostructures, offering a promising pathway toward universal and sustainable wastewater treatment for environmental remediation.

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