Metal-organic frameworks-derived bimetallic oxide composite nanozyme fiber membrane and the application to colorimetric detection of phenol

MOF-derived nanozyme has attracted much attention due to its abundant active sites, great pore structure and diversity of composition. In this work, variable-valence metal Co/Mn bimetallic MOF-74 is used as precursor to prepare bimetallic oxide composite nanozyme with peroxidase-like activity. Compared to monometallic MOFs-derived nanozyme, the coupling of Co and Mn species produces the synergistic effect owing to binary-valence property of Co and Mn, which can promote the catalytic activity. The nanozyme and cellulose are combined to form nanozyme fiber membrane (NFM) through suction filtration. The prepared NFM exhibits stable pore structure and excellent peroxidase-like activity, which can be used to prepare test strip for rapid and in situ detection of phenol. The detection method with the test strip has wide linear range from 0.5 to 500 μM with a low detection limit of 0.2 μM, which is superior to previously reported phenol detection methods. And is successfully applied to in situ and naked-eye detection of phenol in seawater. In our perception, the rational design of bimetallic MOF-derived NFM with special surface physicochemical properties, porous nanostructures and efficient catalytic activity may pave a new path to the development of high-performance in situ detection platforms.