Departmental Seminar: Dr. Erwin Reisner - Re-wiring Photosynthesis for Efficient Solar Water Splitting
In natural photosynthesis, light is used for the production of chemical energy carriers to fuel biological activity. This sustainable process requires the finely tuned combination of light absorption, charge separation and chemical catalysis, which is well evolved, but shows an overall poor efficiency for fuel synthesis. This presentation will summarise our progress in re-engineering photosynthetic pathways to provide inspiration for solar fuel production and to gain insights for understanding the process itself.
Towards this goal, we are developing protein film photoelectrochemistry as a technique to study the light-dependent activity of the water oxidation enzyme Photosystem II adsorbed onto an electrode surface to be studied.1 In particular, we have established the excellent integration of Photosystem II from Thermosynechococcus elongatus on nanostructured and hierarchical inverse opal indium-tin oxide (ITO) electrodes for red light driven water oxidation to O2.2-4 In these studies, protein film photoelectrochemistry was shown to provide us with valuable insights into the activity, stability, quantum yields, and interfacial electron transfer pathways of Photosystem II. Most recently, we succeeded in assembling an efficient enzyme-based full water splitting cell driven by light through the rational wiring of Photosystem II to a [NiFeSe]-hydrogenase from Desulfomicrobium baculatum.4 This hydrogenase displays a combination of unique properties for application in water splitting such as good H2 evolution activity, little product (H2) inhibition and some tolerance towards O2.5,6 These features combined make this enzyme, arguably, the most efficient molecular H2 evolution catalyst for use in water splitting.7 The semi-artificial water splitting cell shows how we can harvest and utilise electrons generated during water oxidation at Photosystem II electrodes for the generation of renewable H2 with a wired hydrogenase through a direct pathway unavailable to biology.
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References:
1) Kato, Zhang, Paul & Reisner Chem. Soc. Rev., 2014, 43, 6485–6497.
2) Kato, Cardona, Rutherford & Reisner J. Am. Chem. Soc., 2012, 134, 8332–8335.
3) Kato, Cardona, Rutherford & Reisner J. Am. Chem. Soc., 2013, 135, 10610–10613.
4) Mersch, Lee, Zhang, Brinkert, Fontecilla-Camps, Rutherford & Reisner J. Am. Chem. Soc., 2015, 137,
8541–8549.
5) Sakai, Mersch & Reisner, Angew. Chem. Int. Ed., 2013, 52, 12313–12316.
6) Caputo, Gross, Lau, Cavazza, Lotsch & Reisner Angew. Chem. Int. Ed., 2014, 53, 11538–11542.
7) Wombwell, Caputo & Reisner Acc. Chem. Res., 2015, DOI: 10.1021/acs.accounts.5b00326.