Structural Motifs in Covalent Organic Frameworks for Photocatalysis

Abstract

Covalent organic frameworks (COFs) attract significant attention due to their ordered, crystalline, porous, metal‐free, and predictable structures. These unique characteristics offer great opportunities for the diffusion and transmission of photogenerated charges during photocatalysis. Currently, a considerable number of COFs are used as metal‐free organic semiconductor photocatalysts. This review aims to understand the relationships between the structure and photocatalysis performance of COFs and provides in‐depth insight into the synthetic strategy to improve photocatalysis performance. Subsequently, the review focuses on the structural motif of COFs in sustainable photocatalytic hydrogen evolution, carbon dioxide reduction, hydrogen peroxide generation, and organic compound transformations. Last, in conjunction with the significant progress achieved and the challenges yet to be overcome, a candid discussion is undertaken regarding the challenges and opportunities in the field of COF photocatalysis, accompanied by the presentation of potential research avenues and future directions. This review seeks to provide readers with a comprehensive understanding of the pivotal role of COFs in the field of photocatalysis, to offer robust guidance for the innovative utilization of COFs in future sustainable photocatalysis.

Advancements in controlling COFs structure for enhanced crystallization properties and self-generated photocatalytic hydrogen peroxide

“…Additionally, the planar molecular configuration of crystalline COFs notably mitigates spatial site resistance effects and conformational freedom, thereby facilitating axial electron migration. 21 Furthermore, the tunable local charge density, coupled with the electron push-pull effect, furnishes kinetic energy for charge migration while diminishing exciton binding and carrier complexation efficiencies.…”

Semiconductor-cluster-loaded ionic covalent organic nanosheets with enhanced photocatalytic reduction reactivity of nitroarenes

“…23 Despite the increasing attention directed towards the application of COF nanosheets in photocatalysis, the exploration of COF-based composites for catalyzing organic transformations is still in its infancy. 24–27 Meanwhile, most studies have only demonstrated the overall photocatalytic performance, with COFs either serving as a photosensitizer or as a solid support, and examples of COFs acting as intrinsic catalysts are relatively scarce. 28 Moreover, the elucidation of the synergistic effects, such as detailed spectroscopic comprehension of exciton and charge carrier dynamics, which are crucial for advancing photocatalytic processes, remains largely unexplored.…”