MOF-Derived Hollow Spheres of MIL-100(Fe)-NH2(20) with Well-Developed Hierarchical Mesoporous and Uniform Distribution of Fe and N Active Phases for the Photocatalytic Removal of Organic Dyes.

Abstract

For the first time, MIL-100(Fe)-derived microspheres with a hollow structure were perfectly constructed and used as a photocatalyst to decompose organic dyes under visible light irradiation. The prepared MIL-100(Fe)-NH2(20) could boost the separation, migration, and transfer of photoinduced carriers effectively, together with efficient photocatalytic performance. In simulated sunlight, the MIL-100(Fe)-NH2(20) exhibits the best degradation efficiency as well as excellent reusability and stability, and the degradation rate for rhodamine B (RhB) can be more than 99.5% within 80 minutes. Structural analysis proves that the porous MIL-100(Fe)-NH2(20) catalyst reaps an amazing hollow structure, large specific surface areas (2784.9 m2·g-1), and uniform distribution of Fe and N active phases. Besides, the enhanced visible light response and lower recombination rate of e--h+ pairs are both confirmed, and the band gap is significantly reduced to 2.53 eV. Finally, the photocatalytic mechanism and the possible degradation pathway were suggested. Owing to the enhanced photocatalytic activity, good tolerance to pH and water quality, and excellent stability, the MIL-100(Fe)-NH2(20) catalyst can be potentially used in a wide range of dye wastewater purifications.