Artificial leaf device for solar fuel production

Abstract

Solar fuels, such as hydrogen gas produced from water and methanol produced from carbon dioxide reduction by artificial photosynthesis, have received considerable attention. In natural leaves the photosynthetic proteins are well-organized in the thylakoid membrane. To develop an artificial leaf device for solar low-carbon fuel production from CO₂, a chlorophyll derivative chlorin-e₆ (Chl-e₆; photosensitizer), 1-carboxylundecanoyl-1′-methyl-4,4′-bipyrizinium bromide, iodide (CH₃V(CH₂)₉COOH; the electron carrier) and formate dehydrogenase (FDH) (the catalyst) immobilised onto a silica-gel-based thin layer chromatography plate (the Chl-V-FDH device) was investigated. From luminescence spectroscopy measurements, the photoexcited triplet state of Chl-e₆ was quenched by the CH₃V(CH₂)₉COOH moiety on the device, indicating the photoinduced electron transfer from the photoexcited triplet state of Chl-e₆ to the CH₃V(CH₂)₉COOH moiety. When the CO₂-saturated sample solution containing NADPH (the electron donor) was flowed onto the Chl-V-FDH device under visible light irradiation, the formic acid concentration increased with increasing irradiation time.