Prof Ron Pace, Prof Rob Stranger, A/Prof Takuya Tsuzuki, Dr George Tsekouras, Dr Richard Terrett, Australian National University, Canberra, ACT 0200
Prof Gerhard (Gerry) F. Swiegers, Dr Pawel Wagner, University of Wollongong, Wollongong, NSW 2522
To make hydrogen efficiently, a good oxygen-generating catalyst is needed at the other electrode …
- The Photosystem II Oxygen Evolving Center (PSII-OEC) that is found in all oxygenic photosynthetic organisms, is the most active water oxidation catalyst known at neutral pH (- up to 1,000 molecules of O2 produced per second per PSII-OEC)
- To date, its catalytic mechanism remains uncertain and attempts to replicate
its activity in man-made, abiological systems have been unsuccessful. In pH 7 water: - The onset voltage (at which catalysis starts) is far lower for the PSII-OEC than any non-biological catalyst
- The catalytic activity of the PSII-OEC is significantly higher than any non-biological catalyst
- In particular, it is not clear why non-biological Mn oxides with a birnessite crystal structure that is identical to the catalytically active Mn3O3 core of the PSII-OEC, do not catalyze water oxidation as well as the PSII-OEC at pH 7