Artificial Thylakoid for the Coordinated Photoenzymatic Reduction of Carbon Dioxide

Artificial photosynthesis holds promise in producing solar fuels and chemicals. Although encouraging achievements have been made in the development of catalysts for reaction/process modules in artificial photosynthesis, constructing a highly compatible complex reaction system remains a distant prospect. Herein, an artificial thylakoid is proposed and constructed by decorating the inner wall of protamine–titania (PTi) microcapsules with cadmium sulfide quantum dots (CdS QDs) for the photobiocoupled reduction of carbon dioxide (CO2) via a single enzyme (formate dehydrogenase) and multiple enzymes (formate/formaldehyde/alcohol dehydrogenases). The size-selective capsule wall compartmentalizes photocatalytic oxidation and biocatalytic reduction, creating well-directed reaction sequences and protecting enzymes from deactivation. The favorable electronic coupling and band structure between CdS and PTi separate holes and electrons to afford an NADH regeneration rate of 4226 ± 121 μmol g–1 h–1 and optimized yield of 93.03 ± 3.84%. The photobiocoupled system achieves formate and methanol outputs of 1500 and 99 μM h–1 with a single enzyme and multiple enzymes, respectively. Our study may exploit a method for the construction of complex artificial catalytic systems with multiple reactions