Assembly of COFs layer and electron mediator on silica for visible light driven photocatalytic NADH regeneration

Photocatalytic regeneration of the high-cost co-factor NADH is a promising method to couple photo-enzyme catalysis, however, the usage of homogeneous electron mediator ([Cp*Rh(bpy)H2O](2+)) which deactivates enzymes deteriorates the whole process efficiency. Herein, we report the immobilization of electron mediator ([Cp*Rh(bpy)H2O](2+)) on covalent organic frameworks (COFs) by the sequential assembly method. The resultant bi-functional photocatalyst with controlled cascade electron transfer afforded NADH production rate of 9.8 mmol.g(COF)(- 1).h(-1), much higher than previously reported ones with integrated electron mediator. The photoenzyme coupling system with the photocatalyst and alcohol dehydrogenase could continuously produce butanol for at least 180 min under visible light irradiation, implying the potential application of bi-functional photocatalyst in artificial photosynthesis.