Engineering Olefin‐Linked Covalent Organic Frameworks for Photoenzymatic Reduction of CO₂

Abstract

It is of profound significance concerning the global energy and environmental crisis to develop new techniques that can reduce and convert CO 2 . To address this challenge, we built a new type of artificial photoenzymatic system for CO 2 reduction, using a rationally designed mesoporous olefin-linked covalent organic framework (COF) as the porous solid carrier for co-immobilizing formate dehydrogenase (FDH) and Rh-based electron mediator. By adjusting the incorporating content of the Rh electronic mediator, which facilitates the regeneration of nicotinamide cofactor (NADH) from NAD + , the apparent quantum yield can reach as high as 9.17 � 0.44 %, surpassing all reported NADHregenerated photocatalysts constructed by crystalline framework materials. Finally, the assembled photocatalyst-enzyme coupled system can selectively convert CO 2 to formic acid with high efficiency and good reusability. This work demonstrates the first example using COFs to immobilize enzymes for artificial photosynthesis systems that utilize solar energy to produce value-added chemicals.

Enabling heterogeneous catalysis to achieve carbon neutrality: Directional catalytic conversion of CO2 into carboxylic acids

“…In addition, the unfavorable energy barrier and sluggish reaction kinetics for producing formic acid can be solved by introducing efficient catalysts. For instance, an enzyme, formate dehydrogenase (FDH), is introduced into the olefin‐linked COFs to form the photocatalyst due to its high activity and selectivity for formic acid formation, 50 although the high cost of large‐scale synthesis of FDH via microbial expression limits its wide application. In addition, some cheap and efficient heterogeneous catalysts such as alpha‐iron oxyhydroxide/Al 2 O 3 , nonporous Pb‐containing polymers (CPs), metalloporphyrin based metal‐catechol frameworks (MCFs) and dual Ti 6 Cu 3 clusters based polymers have been developed to achieve high formic acid yields with the appealing properties such as high visible‐light adsorption, fast charge separation, and transfer efficiency 51–54 .…”

Recent trends in artificial photosynthetic system

“…The reason may be that M acts as a reactive site to facilitate the separation of photogenerated charges. 10 Therefore, research on more efficient, sustainable, and low-cost M immobilization will help to improve the reaction rate and efficiency of artificial photosynthetic systems.…”