In-CdS@ZIF-8&FDH photo-enzyme nanosystem with high NADH regeneration ability via indium doping for enhanced CO₂ reduction to formic acid

Replacement of fossil fuel by renewable resources is a central resource and energy efficiency strategy, where CO2 is the key molecule to proceed effectively in this direction. Here, we synthesized In-doped CdS and constructed a new photo-enzyme nanosystem 10 %In-CdS@ZIF-8&FDH, which can catalyze CO2 to formic acid (HCOOH) via formate dehydrogenase immobilized on ZIF-8 while photocatalytic regenerating NADH via indium-doped CdS. Indium doping greatly enhances the photocatalytic performance of CdS. The NADH regeneration rate reaches 94.10 %. The nanosystem can produce 267.18 mu M HCOOH, which is 4.27 times that of the free enzyme system. And 85.98 % of the residual activity can be retained after reusing 8 times. This study will inspire more research efforts for light-driven enzymatic nanosystems in CO2 fixation and lay the foundation for realizing renewable energy-driven CO2 conversion to produce chemical products.