Circularity-engineered functional 2D materials: advances and commercialization insights for photocatalytic degradation of persistent contaminants

Since the discovery of graphene in 2004, two-dimensional (2D) photoactive materials have gained significant attention owing to their exceptional thermal, electrical, and mechanical properties, as well as their high specific surface area and tunable electronic structure. While photocatalysis remains a promising approach for the degradation of persistent contaminants (PCs), recent advances in materials science have shifted the focus toward 2D material-based heterojunction systems. These systems exhibit abundant reactive sites, enhanced charge transport and separation efficiencies, and robust redox capabilities. This review comprehensively highlights major breakthroughs in 2D metal oxides, transition metal dichalcogenides, metal-free photocatalysts, and MXene-derived heterojunction architectures that demonstrate strong potential for PC detoxification. Furthermore, herein emerging green synthesis strategies that introduce a new dimension to 2D material production, emphasizing the growing use of waste-derived precursors to achieve environmentally benign fabrication, are outlined. Notably, these routes offer dual advantages by lowering production costs and reducing reliance on hazardous chemicals. The article concludes with an integrated perspective on present challenges and future opportunities for 2D heterojunction systems within a circular engineering framework. Finally, the recent progress and commercialization pathways for deploying circularity engineered 2D material-based photocatalytic technologies as sustainable advanced oxidation systems for the effective remediation of PCs are elaborated in detail.