Designed Synthesis of a 2D Porphyrin‐Based sp²Carbon‐Conjugated Covalent Organic Framework for Heterogeneous Photocatalysis

Abstract

The construction of stable covalent organic frameworks (COFs) for various applications is highly desirable. Herein, we report the synthesis of a novel two‐dimensional (2D) porphyrin‐based sp2 carbon‐conjugated COF (Por‐sp2c‐COF), which adopts an eclipsed AA stacking structure with a Brunauer—Emmett—Teller surface area of 689 m2 g−1. Owing to the C=C linkages, Por‐sp2c‐COF shows a high chemical stability under various conditions, even under harsh conditions such as 9 m HCl and 9 m NaOH solutions. Interestingly, Por‐sp2c‐COF can be used as a metal‐free heterogeneous photocatalyst for the visible‐light‐induced aerobic oxidation of amines to imines. More importantly, in comparison to imine‐linked Por‐COF, the inherent structure of Por‐sp2c‐COF equips it with several advantages as a photocatalyst, including reusability and high photocatalytic performance. This clearly demonstrates that sp2 carbon‐linked 2D COFs can provide an interesting platform for heterogeneous photocatalysis.

Pore Surface Engineering of Covalent Triazine Frameworks@MoS2 Electrocatalyst for the Hydrogen Evolution Reaction

“…Notably,t he lattice spacing of MoS 2 in the doping composites is slightly larger than literature report( 0.62 nm), which is attributed to ion intercalation. [28][29][30][31][32][33][34][35] The nitrogen-containing triazine unit in the CTF skeleton can activate the electrons around the carbon,w hich will lead to an outstanding electrochemical performance. [27] Meanwhile, interplanars pacing of 0.27 nm is in accordance with the (1 00) Based on the above,C TFs@MoS 2 -X have ac rystal p-conjugated stacking architecture and hierarchical meso-and micropores in one hybrid system;t his fine structure is facile for fast p-electron hopping,m ass transfer,a nd confinement of the MoS 2 nanoparticles to facilitate large-particle growth.…”

“…In reported 2D CTFs, highly orderedA A( fully eclipsed) stacking leads to large electrostatic coupling and charged elocalization, thus the electron can be not only delocalized effectively in the 2D plane, but also transmitted in the vertical 2D plane direction. [28][29][30][31][32][33][34][35] The nitrogen-containing triazine unit in the CTF skeleton can activate the electrons around the carbon,w hich will lead to an outstanding electrochemical performance. [36,37] More importantly,t he MoS 2 nanoparticles are tightly grown on the surfaceo fc rystal CTFs and the synergistic effect of the coordi-nation of triazine units with Mo atoms will sharplyi ncrease the catalytic active sites, accelerating the mass and charget ransfer in HER.…”

Dynamic Covalent Synthesis of Crystalline Porous Graphitic Frameworks

“…Provided the condensation reaction can be rendered reversible, it may allow error-checking and self-healing to facilitate the growth of crystalline frameworks. Such dynamic covalent reactivity is the basis for the growth of the closely related covalent organic frameworks (COFs), [25][26][27] however, the majority of the known dynamic covalent reactions are limited to non-annulated systems and are not applicable for the synthesis of fully annulated COFs. 28 Synthetic advances that can instill reversibility in annulated ring systems may thus provide a viable solution.…”

2D and 3D Porphyrinic Covalent Organic Frameworks: The Influence of Dimensionality on Functionality

“…Owing to their periodic architectures,l ow densities,h igh surface areas,a nd high stability,C OFs are considered as ah ighly designable and functionalized materials platform with various potential applications.S ince first discovered by Yaghi and co-workers in 2005, [2] intensive attentions have been devoted to constructing functional COFs with desired properties.T hanks to the efforts of many groups,al arge number of functional COFs have been reported over the past decade,w hich have found interesting applications in gas adsorption and separation, [3] heterogeneous catalysis, [4] molecular sensing, [5] energy storage, [6] proton conductivity, [7] and optoelectronics. [8] To construct COFs with desired functionalities,afacile way is incorporating specific functional moieties during their synthesis process.F rom as tructural viewpoint, these functional moieties can be integrated into either two-dimensional (2D) layered structures [9] or three-dimensional (3D) extended networks, [10] depending on the geometry and connectivity of the precursors.F or 2D COFs,the 2D flat sheets usually stack in af ace-to-face mode,a nd the functional moieties in the adjacent layers have strong p-p interactions that could be beneficial for the charge mobility.I nc ontrast, 3D COFs will allow the functional moieties to be three-dimensionally organized into the framework and thus feature open sites.…”