Boosting the Performance of Formate Dehydrogenase by Silver Nanoclusters for Photoreduction of CO₂ to Formate

Abstract

(Photo)Electrochemical CO2 transformation to produce valuable chemicals or biofuels is one of the essential technologies for the carbon-neutral economy to store clean and renewable energy in chemical bonds. Herein, we show an efficient photocatalytic assembly formed by coupling formate dehydrogenase from Clostridium ljungdahliia (ClFDH), silver nanoclusters (AgNCs), TiO2, and graphitic carbon nitride (g-C3N4). The resulting integrated system is stable and can convert CO2 into formate with a turnover frequency of 1 s–1 and a turnover number of over 10,000 in 4 h. We highlight the key roles AgNCs have played to achieve such durability and high efficiency, which include (1) increasing the overall loading of biocatalysts and optimizing the orientation of enzyme molecules upon semiconductors by the Ag–cysteine interaction; (2) as the electron mediator, facilitating the interfacial electron transfer; and (3) scavenging the enzyme-deactivating reactive oxygen species. Our results provide a paradigm of selective CO2-capturing reaction under ambient conditions.