Crystalline Covalent Organic Frameworks Based on Mixed Metallo- and Tetrahydroporphyrin Monomers for Use as Efficient Photocatalysts in Dye Pollutant Removal

Abstract

Unique features, including a high specific surface area, great stability, and crystallinity, make covalent organic frameworks (COFs) intriguing sorbents and catalysts in light-driven water pollutant degradation. Inspired by the light absorption capability of porphyrin derivatives and the carrier separation ability of a donor−acceptor (D−A) configuration, we constructed two-dimensional porphyrin donor-based D−A COFs: COF-HTBD involving only tetrahydroporphyrins and COF-HMTBD (M = Co, Fe, Cu) involving both tetrahydro-and metalloporphyrins via a mixed porphyrin monomer strategy. The monomer 2,1,3-benzothiadiazole-4,7dicarboxaldehyde (BD) is incorporated as an electron accepting moiety. Interestingly, COF-HTBD, COF-HCuTBD, and COF-HFeTBD exhibit staggered stacking, while the stacking model of COF-HCoTBD transforms from staggered to eclipsed. Notably, COF-HFeTBD demonstrates excellent activities and stabilities toward visible light-driven photocatalytic rhodamine B (RhB) degradation in aqueous solutions with H 2 O 2 present (100% removal in 3 h). Overall, this work provides an interesting strategy for the construction of D−A-type porphyrin COFs for dye pollutant removal.

Mechanically Activated Covalent Organic Framework as Metal Free Photocatalyst for Continuous Flow Fenton-like Degradation of Organic Pollutants and Hexavalent Chromium Reduction

“…Accordingly, CF factors of various photocatalysts were compared with the reported literatures. The CF value of dDAAQ-TFP is 10.28, which is 26582, 243, 10 and 10 times greater than the COF-HTBB, 7 MWCNT, 3 Tp-Mela, 2 and CN600, 5 respectively. Most recently, Tp-Mela COF has been shown to be a highly effective metal-free carbonaceous photocatalyst for Fenton-like photodegradation.…”

“…For instance, multiwalled carbon nanotubes (MWCNT), 3 reduced graphene oxide, 4 graphitic carbon nitride, 5 and photoelectron-Fenton like cell, 6 and COF-THTBD. 7 Among them, triazine linked Tp-Mela COF is reported as highly active photo Fenton-like activities over several colored and colorless pollutants. The efficiency of the Tp-Mela COF photocatalyst is much higher even than several metal-based photo Fenton-like systems.…”

Reversed Regulation Effects of ssDNA on the Mimetic Oxidase and Peroxidase Activities of Covalent Organic Frameworks

“…[32] Compared with other photosensitive materials, COFs have better photocatalytic activity due to the extended π-conjugated frameworks, excellent crystallinity, and ordered pore structures. [33] In the past few decades, COFs containing porphyrins and their metal derivatives, [34][35][36][37] benzothiadiazole [38][39][40] or triazine [41][42][43] involve excellent photoelectric properties and demonstrate great potential in the fields of photocatalysis. On the basis of the excellent photoelectric property of COFs, it can be predicted that COFs also have unique nanozymatic activities and demonstrate great potential in the field of nanozymes.…”

Boosting Exciton Dissociation and Charge Transfer in Triazole-Based Covalent Organic Frameworks by Increasing the Donor Unit from One to Two for the Efficient Photocatalytic Elimination of Emerging Contaminants

“…Developing facile and cost-effective intermolecular modulating strategies to improve the dissociation of excitons and enhance the charge transfer in COFs thus is in great demand. , Via the electronic push–pull effect between donor and acceptor units, the donor–acceptor (D–A) structure constructed within COFs has been demonstrated to be one of the most promising intermolecular modulating strategies to decrease the exciton binding energy ( E b ) and facilitate charge transfer. − For example, Liu et al found that porphyrin-based D–A COF (COF-HFeTBD) could facilitate charge separation and transfer, improving the photodegradation performance of rhodamine B. Yang et al also showed that conjugated D–A COF (TAPP-BDP) without any postsynthesis modification exhibited high antibacterial efficiency due to the efficient charge separation efficiency. Very recently, we fabricated a thiadiazole-based D–A COF (COF-TD1) with a rapid intramolecular charge transfer process (IRCT), which exhibited efficient photocatalytic degradation performance toward emerging contaminants .…”