Bio-inspired Preparation Of Amorphous Titania Coating For Photocatalytic NADH Regeneration Intensification

Due to the high activity and selectivity,enzymatic hydrogenation exhibits great promise in the production of pharmaceutical intermediates and fine chemicals.However,most of the enzymatic hydrogenation reactions consume expensive NAD(P)H for the selective reduction of the substrates.Inspired by photosynthesis,using solar energy to power the regeneration of NAD(P)H should promote the application of enzymatic hydrogenation.Herein,we coordinate three steps of photocatalytic NADH regeneration,including light-induced charge separation and transfer,NADH reduction,and diffusion and oxidation of electron donor,by manipulating the chemical,physical and electronic structure of amorphous titania for efficient photocatalytic NADH regeneration.Then,we couple the photocatalytic NADH regeneration with enzymatic hydrogenation to promote the performance of the enzyme-photo coupling catalytic system.The details of this thesis were summarized as follows:The coordination of light induced charge separation and transfer,and diffusion and oxidation of electron donor for efficient photocatalytic NADH regeneration:we constructed graphitic carbon nitride(GCN)@amorphous titania(a-TiO2)core-shell photocatalyst by depositing amorphous titania on GCN through biomimetic mineralization.The electronic and physical structure of amorphous titania were manipulated to coordinate the light induced charge seperation and transfer,and diffusion and oxidation of electron donor.NADH regeneration rate was 0.12 mmol g-1 min-1,which was increased by 2 times than GCN.The coordination of light induced charge separation and transfer,and NADH reduction for efficient photocatalytic NADH regeneration:[Cp*Rh(bpy-COOH)H2O]2+was immobilized on amorphous titania shell through the synergy of biomimetic mineralization and assembly.The chemical and electronic structure of[Cp*Rh(bpy-COOH)H2O]2+-titania shell were manipulated to coordinate the light induced charge separation and transfer,and NADH reduction.The optimum NADH regeneration yield was 60%after 20 min visible light illumination,which was increased by 2.2 times than the coupling of free[Cp*Rh(bpy-COOH)H2O]2+and GCN.The coordination of photocatalytic NADH regeneration and enzymatic hydrogenation for an efficient enzyme-photo coupling catalytic system:the influence of the catalytic components on the activity of yeast alcohol dehydrogenase(YADH)under dark and light conditions was evaluated.The photocatalytic NADH regeneration and enzymatic hydrogenation were coordinated by compartmentalizing the photo-generated holes and[Cp*Rh(bpy)H2O]2+with YADH through amorphous titania.The optimized methanol concentration was 14.4 mM,and the cycle number of NADH was 3.6.