Two‐Dimensional Covalent‐Organic Frameworks for Photocatalysis: The Critical Roles of Building Block and Linkage

Abstract

Covalent organic frameworks (COFs) are a class of crystalline porous materials which contain organic build blocks linked via covalent bonds to form ordered and periodic structures. In recent years, 2D COFs have been developed as promising heterogeneous photocatalysts due to their extended π‐conjugated skeletons, high surface area, tunable structure, regular pore structure, and high crystallinity. Herein, recent advances in the design and synthesis of 2D COFs for photocatalysts are surveyed, the illustration of the structural features and synthetic strategy is focused on, and the relationship between the construction and property of 2D COFs for photocatalytic water splitting, CO2 reduction, organic transformation, and degradation of organic pollutants is elucidated. This overview is expected to provide clues to rational design and synthesis of ultra‐stable, high crystalline, and high‐performance 2D COFs for photocatalytic applications.

2D–2D SnS2/Covalent Organic Framework Heterojunction Photocatalysts for Highly Enhanced Solar-Driven Hydrogen Evolution without Cocatalysts

“…Photocatalytic water splitting to convert the solar source into renewable H 2 energy by artificial semiconductors has been extensively considered to be an inexhaustible solution. − Since the first report by Yaghi in 2005, covalent organic frameworks (COFs) have attracted broad attention owing to their large surface area, well-organized structure and high chemical stability in catalysis, , optoelectronics, , energy storage, , and so forth. Two-dimensional COFs (2D COFs), − especially in the representative ketoenamine-based TpPa-1-COF, − have been shown to be superior to some traditional single-component inorganic semiconductors in photocatalytic H 2 evolution. − Nevertheless, due to the exciton effect caused by the Coulomb interaction between photoelectron–hole pairs, , the high recombination rate makes it difficult to further enhance the photocatalytic performance of single-component COF-based photocatalysts. , Moreover, to speed up the surface reaction kinetics, platinum and other high-priced precious metal cocatalysts are inevitably applied in the catalytic process. , …”

An Eosin Y Encapsulated Cu(I) Covalent Metal Organic Framework for Efficient Photocatalytic Sonogashira Cross-coupling Reaction

“…2(F)]. The above optical and electrochemical measurements clearly demonstrate the introduction of EY dye into JNM-1 would narrow the band gap, leading to a smaller barrier of photocarrier transfer and higher charge separation efficiency, which may enhance the photocatalytic performance [32][33][34] .…”

Fabrication of NanoCOF/Polyoxometallate Composites for Photocatalytic NADH Regeneration via Cascade Electron Relay

“…[ 1,2 ] 2D COFs with a variety of ordered π systems provide a desirable platform for developing visible‐light responsive photocatalysts for solar energy storage and conversion and have already shown potential applications in photocatalytic water splitting, CO 2 reduction, and organic synthesis. [ 3–11 ] In regardless of suitable bandgap and band structure, COFs in most cases afforded very low quantum efficiency in photocatalysis. Considering that the separation and transportation of the photogenerated charges is the key step in photosynthesis, the fast extraction of photogenerated electrons confined in π orbitals of COFs is very important for efficient photosynthesis.…”