Theory-Driven Design and Targeting Synthesis of a Highly-Conjugated Basal-Plane 2D Covalent Organic Framework for Metal-Free Electrocatalytic OER

Abstract

It is a great challenge to obtain oriented design and synthesis of new two-dimensional covalent organic frameworks (2D-COFs) with proper CN stoichiometry, N position, and band structures as specific electrocatalysts. Driven by density functional theory (DFT) calculations, we designed and synthesized a new phenazine-linked 2D-COF (COF-C 4 N) by solvothermal reaction of triphenylenehexamine (TPHA) and hexaketocyclohexane (HKH). Structural analysis confirmed that COF-C 4 N possesses an ordered crystalline structure with a highly conjugated basal plane and better stability. COF-C 4 N exhibited OER performance with a low overpotential of 349 mV at 10 mA cm −2 and a Tafel slope of 64 mV dec −1 . A combination of theoretical and experimental studies revealed that better OER performance is attributed to better crystallinity and stability, an appropriate band gap, and an N position that promotes the formation of C active sites around N atoms. The strategy of theory-driven design and targeting synthesis of 2D-COFs for OER may provide a new way to further develop metal-free materials for clean energy application.

Electroactive Covalent Organic Frameworks: Design, Synthesis, and Applications

“…Meanwhile, reticulating COF structures by controlling elemental composition such as CN stoichiometry and N position could also transform COFs into promising metal‐free electrocatalyst for OER. One representative report of this approach was the reported phenazine‐linked COF‐C 4 N. [ 219 ] All these reports describe the feasibility of COF as promising OER electrocatalyst by structural composition tuning.…”

Inorganic nanocrystal-dynamic porous polymer assemblies with effective energy transfer for sensitive diagnosis of urine copper

“…Covalent organic frameworks (COFs), based on the autoassembly of aromatic units through the reversible character of polymerization reactions, are a type of dynamic porous polymer. [13][14][15][16] Due to their designable building blocks and tunable porous structures, COFs have been considered to be functional organic equivalents of inorganic microporous solids for utilization in gas separation, [17][18][19] ion enrichment, 20 optoelectronics, [21][22][23] catalysis, [24][25][26] drug transport, 27,28 and biosensing. [29][30][31][32] Based on the reversible formation of covalent bonds, they combine error-correction capability and molecular robustness.…”

Capturing Visible Light in Low‐Band‐Gap C4N‐Derived Responsive Bifunctional Air Electrodes for Solar Energy Conversion and Storage

“…The high-resolution N1ss pectrum of C 4 N/CP can be deconvoluted into ap eak at 400.1 eV corresponding to pyrazine-like N-C signals and ap eak at 398.9 eV derived from residual -NH 2 groups,s imilar to C 4 Np owder (Figure 1d;F igure S4). [23,24] Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observation of C 4 N/CP uncovered au niform coating layer consisting of numerous C 4 N particles with the size of several hundreds of nanometers on the carbon fiber surface of CP,i ns tark contrast to rather smooth surface of original CP (Figure 1e-g). Elemental mapping results of individual C 4 Ncoated carbon fiber clearly revealed the homogeneous distribution of Cand Ninthe C 4 N coating layers (Figure 1h).…”