A comprehensive review on bismuth-based ternary heterojunctions in photocatalytic wastewater treatment

Bismuth-based ternary heterostructured photocatalysts have emerged as one of the most promising classes of materials for wastewater treatment, owing to their narrow band gaps, high structural versatility, and capacity to facilitate efficient charge carrier separation under solar irradiation. Recent studies demonstrate that integrating Bi₂WO₆, BiVO₄, BiOX, Bi₂MoO₆, Bi₂O₃, Bi₂S₃, or multi-bismuth phases into ternary configurations, particularly Z-scheme, S-scheme, and dual heterojunction architectures, substantially enhances photocatalytic performance by accelerating interfacial electron transport while preserving strong redox potentials. These systems consistently achieve high degradation efficiencies across dyes, pharmaceuticals, antibiotics, pesticides, and emerging contaminants, frequently outperforming binary and single-component counterparts. Key advances include the use of carbonaceous scaffolds to broaden visible-light absorption, magnetic and transition-metal components to strengthen redox cycling, and defect or vacancy engineering to intensify surface reaction kinetics. Comparative evaluation across recent reports reveals that the most efficient ternary systems often couple broad-spectrum light harvesting with strong built-in electric fields that drive directional charge migration. Despite these advances, persistent challenges remain regarding interfacial stability, secondary pollution risks, and scalability of synthesis routes. Overall, the rapidly evolving evidence indicates that bismuth-based ternary heterostructures represent a highly adaptable, high-performance platform for future solar-driven wastewater treatment, with clear opportunities for optimization through targeted band engineering, green synthesis strategies, and improved photonic utilization.