Metal Hydride-Embedded Titania Coating to Coordinate Electron Transfer and Enzyme Protection in Photo-enzymatic Catalysis

Albeit that photo-enzymatic catalysis has sparked more and more attention, its efficiency is restricted by lower electron transfer and poor compatibility between the natural enzyme and synthetic photocatalyst. Herein, a metal hydride-embedded titania (MH/TiO2) coating is engineered on graphitic carbon nitride (GCN) to coordinate electron transfer and enzyme protection for photo-enzymatic alcohol production. The MH/TiO2 coating plays two vital roles: (1) protecting alcohol dehydrogenase (ADH) from deactivation by the GCN core and MH in the coating and (2) permitting electron transfer from GCN to nicotinamide adenine dinucleotide (NAD+) and then to formaldehyde catalyzed by ADH. The coordinated photo-enzymatic system could produce methanol at a rate of 1.78 ± 0.21 μmol min–1 mg(ADH)−1, which is 420% higher than that of the system composed of ADH and GCN without the coating. Moreover, the coordinated system could continuously produce methanol for at least three light–dark cycles, while the system composed of GCN and ADH is completely deactivated after one light–dark cycle. Our study unveils the potential of redox-active mineral coating in coordinating synthetic and biological modules for solar chemical conversion.