Bimetallic MOFs/MXene-derived heterogeneous photocatalyst for enhanced adsorption and synergistic photo-Fenton degradation of methylene blue

The development of iron-based heterogeneous Fenton catalysts is often hindered by challenges including slow Fe 3+ /Fe 2+ cycling, limited interfacial electron transfer kinetics, and inefficient mass transport, leading to suboptimal catalytic efficiency. In this work, three distinct assembly strategies—hydrogen bonding, electrostatic self-assembly, and solvothermal methods—were utilized to fabricate MCuFe-MOF/PMMA@MXene (denoted as MPM) microspheres for the photo-Fenton degradation of methylene blue (MB). Notably, the microspheres fabricated via electrostatic self-assembly (designated E -MPM) exhibited a unique three-dimensional (3D) microsphere architecture. This structure significantly enhanced the adsorption capacity for pollutants and improved mass transfer, concurrently broadening the visible-light absorption range. The well-defined interfaces within the E -MPM microspheres facilitate the formation of multiple heterojunctions with favorable band alignment, which effectively promotes the generation and separation of photogenerated electron-hole pairs. Consequently, highly reactive free radicals are efficiently generated through the photo-Fenton process, the E -MPM microspheres demonstrated high catalytic activity, achieving a remarkable MB degradation efficiency of approximately 91.9% within 60 min at 4 g/L MB under visible-light irradiation. This study not only provides a fundamental insight into the design of bimetallic MOF/MXene-derived heterogeneous photocatalysts, but also broadens the application scope of MXene-based materials in advanced water treatment technologies.