Hierarchically Structured NH2-MIL-125/TiO2/Cellulose Composite Membranes With Enhanced Photocatalytic Performance

A cellulose-based photocatalytic membrane was fabricated by in situ growth of the NH2-MIL-125 nanoparticles onto the surfaces of the ultrathin titania (TiO2) gel layers pre-coated cellulose nanofibres of natural cellulose substance (commercial laboratory filter paper). The NH2-MIL-125 nanoparticles were grown on the surface of the titania gel coated cellulose nanofibres via a one-step solvothermal method. The resultant composite membranes maintained the initial hierarchical network structures of the bulk cellulose substance, consisting titania gel layer coated cellulose nanofibres with NH2-MIL-125 nanoparticles anchored on the surfaces. Owing to the hierarchical porous structure of the cellulose substrates as well as the effective heterostructure formation between the NH2-MIL-125 particles and the TiO2 layers, the composites showed enhanced photocatalytic performances. The NH2-MIL-125/TiO2/cellulose composite composed of 15.82 wt% NH2-MIL-125 content with nanoparticles sizes of 100-200 nm showed an apparent rate constant of 0.032 min(-1) in photocatalytic degradation of Rhodamine B (RhB), which was higher than those of the NH2-MIL-125/cellulose composite and the TiO2/cellulose composite. It was demonstrated that pre-coating of the cellulose nanofibres with ultrathin titania gel layers was essential for the growth of the NH2-MIL-125 nanoparticles thereon.