Solvent-Induced Two Co-Based 3D Metal–Organic Frameworks as Platforms for the High Degradation of Rhodamine B Under Sunlight

Abstract

Photocatalytic degradation of rhodamine B (RhB) is an extremely difficult but very important issue in the field of environment protection. Two metal–organic frameworks (MOFs) [Co3(L) (NTB)2(DMA)2]·4DMA (1) and [Co3(L) (NTB)2]·2DMA (2) [L = (E)-4,4′-(ethene-1,2-diyl)­bis­(N-pyridin-3-yl)­benzamide, H3NTB = 4,4′,4″-nitrilotribenzoic acid] were successfully synthesized by tuning the acidity of the solvent under the solvothermal conditions. MOFs 1 and 2 exhibited the same composition but different metal coordination modes, which displayed excellent photocatalytic activities toward the degradation of RhB without any additional oxidants or co-catalysts under true sunlight. The degradation ratio of RhB reached over 96% within 30 min, and the selectivity toward RhB of MOFs 1 and 2 was also investigated. The effect of solvents on the photocatalytic degradation of RhB was explored. In addition, the stable cycle-catalytic efficiencies of 1 and 2 indicated that they possessed not only outstanding photocatalytic activities but also good reusability toward the degradation of organic dye RhB, enabling them to become potential candidates for environmental governance.

New two fold interpenetrating 3D polyoxovanadate-based metal–organic framework as bifunctional catalyst for the removal of 2-chloroethyl ethyl sulfide and phenolic compounds

“…The reaction kinetics of the photocatalytic process agrees with the pseudo-first-order mode corresponding to the Langmuir-Hinshelwood model, as shown in Fig.4(b)[56]. In addition, ln(c 0 /c) has a good linear relationship with the reaction time[57]. The linear correlation coefficients (R 2 ) are greater than 0.9.…”

Assembly of Functional Co(II) Metal–Organic Frameworks through a Mixed Ligand Strategy: Structure and Photocatalytic Degradation Properties

“…Metal–organic frameworks (MOFs) are crystalline structural materials with periodic infinitely extended networks formed by metal ions or metal clusters connected to organic ligands through coordination bonds. − Compared to traditional inorganic and organic materials, MOFs are characterized by controllable structure, large porosity, ultrahigh specific surface area, etc. − Thus, MOFs have been widely applied in various fields such as adsorption and separation of gases, sensing, and proton conduction. − Cobalt MOFs were widely used in the field of catalysis due to their excellent chemical stability, eminent catalytic activity, rich geometries (octahedral, tetrahedral, or square planar), and variable oxidation states (Co­(II) and Co­(III)). − In addition, many Co-MOFs have small band gaps and high-density catalytic centers, exhibit semiconducting properties under irradiation, and can be used as novel heterogeneous photocatalysts. − For example, Fan and co-workers reported four Co-MOFs, which showed good photocatalytic activity in the degradation of methyl violet (MV), methylene blue (MB), and rhodamine B (RhB) under a Hg lamp source . A cobalt-based MOF with two-fold interpenetrating structures used in the detection, discrimination, and degradation of phenolic pollutants was reported .…”

Effective photocatalytic degradation of rhodamine-B over Zn-doped BaO2 and SrO2 composites under UV and sunlight irradiation

“…RhB is difficult to degrade. 12 To date, numerous treatment techniques have been researched to remove water contaminants, including physical, biological, and semiconductor-based photocatalysis. 13,14 Among these methods, semiconductor catalysis has attracted much attention as a “green”, energy-saving, and economically advanced oxidation process.…”