Electrochemical Sensors Based on Covalent Organic Frameworks: A Critical Review

Abstract

The metal-free cousins of metal-organic frameworks, covalent organic frameworks (COFs), are a class of pre-designable crystalline polymers composed of light elements and connected by strong covalent bonds. COFs are being given more and more attention in the electrochemical sensor field due to their fascinating properties, such as highly tunable porosity, intrinsic chemical and thermal stability, structural diversity, large specific surface area, and unique adsorption characteristics. However, there are still some key issues regarding COFs that need to be urgently resolved before they can be effectively applied in electrochemical sensing. In this review, we summarized recent achievements in developing novel electrochemical sensors based on COFs, and discussed the key fundamental and challenging issues that need to be addressed, including the mechanisms underlying charge transport, methods to improve electrical conductivity, immobilization methods on different substrates, synthesis strategies for nanoscale COFs, and the application of COFs in different fields. Finally, the challenges and outlooks in this promising field are tentatively proposed.

Covalent organic frameworks (COFs) for electrochemical applications

“…Electrochemical sensors have gained extensive attention for the analysis of species of biological, environmental and industrial interest. 270 Typically, an electrochemical sensor consists of a working electrode and a counter electrode connected by a certain electrolyte. Through the reaction between working electrode and analytes, electric signals can be recorded, which are proportional to the analyte concentrations.…”

Gold Nanomaterials-Based Electrochemical Sensors and Biosensors for Phenolic Antioxidants Detection: Recent Advances

“…A sensor based on covalent organic frameworks (COFs) doped with AuNPs was developed for the determination of GCA in spiked real samples of coffee, apple juice, and honeysuckle [ 103 ]. COFs represent a class of multifunctional porous crystalline materials, involving 2D or 3D porous crystalline architectures composed of light elements (C, B, O, Si, and N) via strong covalent bonds (C-N, C=N, C=C-N, B-O) [ 104 , 105 , 106 , 107 ]. It is well known that AuNPs need a stabilizing and dispersing agent to avoid their aggregation and agglomeration.…”

Computational investigation of a covalent triazine framework (CTF-0) as an efficient electrochemical sensor

“…In the past few years, COFs became the center of attention for researchers, due to their highly porous surface, structural properties, physical and chemical durability as well as exhibiting strong covalent bonding. [12][13][14] Covalent triazine-based frameworks (CTFs) are considered as a novel promising class of organic porous crystalline materials, rst prepared by Thomas et al in 2008. CTFs can be synthesized by trimerization reaction of aromatic nitrile in molten ZnCl 2 under ionothermal conditions.…”