Development of a Semi-Artificial Chloroplast

ended

The transition to a green and sustainable energy-based economy is one of the most critical challenges of our society. In this line, the production of chemicals and fuels from renewable energy, CO2 and water as primary feedstocks is an attractive alternative to solve the increasing worldwide demand for resources. Taking inspiration from Natural Photosynthesis, where sunlight energy is stored into chemical bonds producing only O2 as a by-product, an appealing approach is the use of sunlight as a driving force to produce renewable fuels from CO2 and water using artificial photosynthesis (AP). Unfortunately, efficient CO2 reduction and water oxidation (WO) remain bottlenecks in the development of efficient AP. Particularly challenging is the selective CO2-reduction due to the number of accessible reaction pathways with a similar thermodynamic reduction potential. The current proposal aims to develop a semiartificial photosynthetic system to revolutionise solar fuel production taking the advantages of both biologic (selectivity and low energy barriers due to structural complexity) and synthetic molecular systems (efficiency and straightforward modification and study) and overcome the limitations of both worlds themselves. This is a unique approach where the combination of natural enzymes with artificial systems (metal catalysts, light absorbers and synthetic membranes) will lead to new solar-fuel production schemes not achievable by natural or molecular catalysts alone. As such, SmArtC aims to embed Photosystem II (PSII), in a membrane of a liposome and couple its WO activity with the photocatalytic CO2-reduction-to-methane reactivity of a highly efficient and selective dual photocatalytic system based on an iron porphyrin catalyst and an organic dye, also embedded into the liposome. This proposal would achieve the long-standing goal of the use of water as an electron donor, CO2 as primary carbon feedstock and sunlight as a driving force to produce carbon-based fuels.