Molecular science for solar fuels - recent results in natural and artificial photosynthesis

Stenbjörn Styring

Department for Photochemistry and Molecular Science, Molecular Biomimetics. The Ångström Laboratory, Uppsala University, Box 256, 751 05 Uppsala, Sweden




The lecture will cover visions and strategies in research in the Swedish Consortium for Artificial Photosynthesis and the European network SOLAR-H2. Our research aims for the production of hydrogen, from the endless resources solar energy and water. Our main idea is that water shall be oxidized in a molecular, catalytic process using solar energy. The electrons from water shall then be used in a second catalytic process to reduce protons to molecular hydrogen. We follow two scientific branches to accomplish solar fuels, artificial photosynthesis in entirely manmade systems and photobiological solar fuels production in green algae and cyanobacteria. In our attempts to accomplish artificial photosynthesis we use a biomimetic approach where we copy key principles from natural enzymes that accomplish partial reactions. Water oxidation using solar energy is carried out by Photosystem II using a catalytic Mn4 complex. In our chemistry we use a photoactive Ru-center that is coupled to synthetic multinuclear manganese-complexes. I will describe some results from our research on light driven, multi-electron transfer in these Ru-Mn systems and a recent water oxidizing catalyst based on a cobalt nano-particle. To accomplish reduction of protons to hydrogen we mimic the di-iron center in hydrogenase enzymes. Some recent results on these biomimetic Fe-Fe complexes will be described.

The lecture will also describe recent results on the redox situation in Photosystem II that is developed during so called sulphur deprivation - a much studied method to produce hydrogen in the green algae Chlamydomonas reinhardtii.