Development of an Integrated System for Highly Selective Photoenzymatic Synthesis of Formic Acid from CO₂

Abstract

Herein, a Zr‐based dual‐ligand MOFs with pre‐installed Rh complex was employed for NADH regeneration in situ and also used for immobilization of formic acid dehydrogenase (FDH) in order to realize a highly efficient CO2 fixation system. Then, based on the detailed investigations into the photochemical and electrochemical properties, it is demonstrated that the introduction of the photosensitive meso‐tetra(4‐carboxyphenyl) porphin (TCPP) ligands increased the catalytic active sites and improved photoelectric properties. Furthermore, the electron mediator Rh complex, anchored on the zirconium‐based dual‐ligand MOFs, enhanced the efficiency of electron transfer efficiency and facilitated the separation of photogenerated electrons and holes. Compared with UiO‐66‐NH2, Rh‐H2TCPP‐UiO‐66‐NH2 exhibits an optimized valence band structure and significantly improved photocatalytic activity for NAD+ reduction, resulting the synthesis of formic acid from CO2 increased from 150 μg mL−1 (UiO‐66‐NH2) to 254 μg mL−1 (Rh‐H2TCPP‐UiO‐66‐NH2). Moreover, the assembled photocatalyst‐enzyme coupled system also allows facile recycling of expensive electron mediator, enzyme, and photocatalyst.

Direct Biocatalytic Processes for CO2 Capture as a Green Tool to Produce Value-Added Chemicals

“…Photochemical reactions are another suitable approach to reducing CO 2 [ 31 , 229 , 230 , 231 , 232 ]. The energy arises from light, which is an inexpensive, renewable, and clean source.…”

“…that make them ideal for catalysis in general, and photobiocatalysis in particular. An excellent recent example is Xing’s work [ 229 ], where a porphyrin ligand was covalently bound to a Zr-based MOF and, posteriorly, the complex Cp*Rh(bpydc)Cl 2 (bpydc = 2,2′-bipyridine-5,5′-dicarboxylic acid) was incorporated into the organic frame, generating a system that can be activated by light owing to the porphyrin, the Rh(III) complex, and original aromatic ligands of the MOF. FDH was then immobilized via electrostatic entrapment.…”

“…First, owing to the low redox potential of the CO 2 /HCO 2 − pair (−430 mV), the reaction is highly endergonic under physiological conditions. Three main strategies have been developed to overcome this problem (Figure 8): coupling thermodynamically favorable reactions in the presence of an excess concentration of the reducing agent [136,[221][222][223][224]; coupling the reaction to an electrochemical device that provides electrons from a battery anode (i.e., by supplying electric energy) [225][226][227][228]; and using photosensitive molecules able to absorb light and regenerate redox partners [31,[229][230][231][232][233]. Regeneration of the cofactor NADH is crucial for obtaining formate with acceptable yields [234][235][236][237].…”

Metal-Free Light-Driven 1,4-NADH Regeneration System from Nitrogen and Sulfur Codoped Carbon Dots

“…The reduced form of nicotinamide cofactors, such as NADH and its phosphorylated derivative (NADPH), serve as crucial reducing equivalents for cellular redox homeostasis and in vitro enzyme-catalyzed reactions. , Nearly 80% of oxidoreductases consume NAD­(P)H to drive redox reactions. , Although the high cost restricts industrial application of these cofactors, NAD­(P)H could be used if regeneration were implemented. Therefore, it is urgent to explore green and efficient methods for NAD­(P)H regeneration. , In recent years, inspired by natural photosynthesis, photocatalytic NAD­(P)H regeneration has become an emerging solution due to the abundant solar energy, gentle reaction condition, and high sustainability.…”

“…Therefore, it is urgent to explore green and efficient methods for NAD(P)H regeneration. 5,6 In recent years, inspired by natural photosynthesis, photocatalytic NAD(P)H regeneration has become an emerging solution due to the abundant solar energy, gentle reaction condition, and high sustainability.…”