π-Electron-Extended Triazine-Based Covalent Organic Framework as Photocatalyst for Organic Pollution Degradation and H2 Production from Water

Abstract

Herein, we report the efficient preparation of π-electron-extended triazine-based covalent organic framework (TFP-TPTPh COF) for photocatalysis and adsorption of the rhodamine B (RhB) dye molecule, as well as for photocatalytic hydrogen generation from water. The resultant TFP-TPTPh COF exhibited remarkable porosity, excellent crystallinity, high surface area of 724 m2 g−1, and massive thermal stability with a char yield of 63.41%. The TFP-TPTPh COF demonstrated an excellent removal efficiency of RhB from water in 60 min when used as an adsorbent, and its maximum adsorption capacity (Qm) of 480 mg g−1 is among the highest Qm values for porous polymers ever to be recorded. In addition, the TFP-TPTPh COF showed a remarkable photocatalytic degradation of RhB dye molecules with a reaction rate constant of 4.1 × 10−2 min−1 and an efficiency of 97.02% under ultraviolet–visible light irradiation. Furthermore, without additional co-catalysts, the TFP-TPTPh COF displayed an excellent photocatalytic capacity for reducing water to generate H2 with a hydrogen evolution rate (HER) of 2712 μmol g−1 h−1. This highly active COF-based photocatalyst appears to be a useful material for dye removal from water, as well as solar energy processing and conversion.

Donor–acceptor hetero[6]radialene-based three-dimensional covalent organic frameworks for organic pollutant adsorption, photocatalytic degradation, and hydrogen production activity

“…This structural arrangement is upheld by several robust hydrogen bonds formed between the carbonyl (CO) groups and the amino (N–H) groups. 71…”

Covalent Trapping of Cyclic-Polysulfides in Perfluorinated Vinylene-Linked Frameworks for Designing Lithium-Organosulfide Batteries

“…To further validate the mechanism, in situ Raman studies 32 were conducted on customized coin cells (Scheme S2) by monitoring the spectral changes during redox reactions in the Li-OrSB within the voltage range 1−3 V using Type-I electrolyte (Figure 3, Figures S29 and S30). The intensity of the signals for triazine −C�N 33 in sp 2 -COF2-S appeared at 1530−1576 cm −1 and varied reversibly upon converting to the −C−N signal at 1350 cm −1 during lithiation at low discharge potentials of 1 V (Figure 3B). 15 The quinoxaline −C�N signal 34 of sp 2 -COF2-S at 1545 cm −1 also exhibited the reversible broadening of the signal in terms of quinoxaline radical intermediate formation at 1400 cm −1 along with the appearance of a new signal at 1320 cm −1 for reversible conversion to −C−N (Figure 3B) during lithiation.…”

Heterosporous Phenylpyridine-Based Covalent Organic Framework Microflowers for Highly Selective Sensing of Hydrogen Sulfide

“…This, in turn, leads to an improvement in the stability of the overall structure. − Notwithstanding this benefit, the achievement of their synthesis still poses challenges because of the indeterminate structural regularity under solvothermal conditions. , Therefore, the rational manipulation and control of organic micro/nanoflowers hold significant importance. Covalent organic frameworks (COFs) are a new family of crystalline porous organic polymers. − With the advantages of low density, structural diversity, periodic and uniform porosity, enormous surface area, thermal stability, permanent crystallinity, and versatile functionalities, COFs are promising materials for a considerable variety of applications, such as heterogeneous catalysis, gas storage and separation, molecular separations, chemical sensing, energy conversion and storage, semiconductors, and drug delivery. − Nevertheless, most conventional COFs are produced and isolated in the form of microcrystalline powders, hence restricting the efficient exploitation of active sites. In the recent literature, there have been reports on the rational design of COF nanomaterials with precise crystalline forms and consistent pore size distributions, aiming to enhance their characteristics and expand their potential uses .…”