Project summary
Leaves can split water into O
2 and H
2 at ambient conditions exploiting sun light.
James Barber, one of the key players of ArtipHyction, elucidated Photosystem II
(PSII), the enzyme that governs this process. In photosynthesis, H
2 is used to reduce
CO
2 and give rise to the various organic compounds needed by the organisms or even
oily compounds which can be used as fuels. However, a specific enzyme, hydrogenase,
may lead to non-negligible H
2 formation even within natural systems.
Building on the pioneering work performed in a FET project based on natural enzymes
(Solhydromics, FP7-Energy-2008-FET) and the convergence of the work of the physics,
materials scientists, chemical engineers and chemists involved in the project, an
artificial device will be developed to convert sun energy into H
2 with close to
10% efficiency by water splitting at ambient temperature, including:
-
an electrode
exposed to sunlight carrying a PSII-like chemical mimic deposited upon a suitable
transparent electronconductive porous electrode material (e.g. ITO, FTO);
- a membrane enabling transport of protons via a pulsated thin water gap;
- an external
wire for electron conduction between electrodes;
- a cathode carrying an hydrogenase-enzyme
mimic over a porous electron-conducting support in order to recombine protons and
electrons into pure molecular hydrogen at the opposite side of the membrane.
A tandem system of sensitizers will be developed at opposite sides of the membrane
in order to capture light at different wavelengths so as to boost the electrons
potential at the anode for water splitting purposes and to inject electrons at a
sufficiently high potential for effective H
2 evolution at the cathode. Along with
this, the achievement of the highest transparence level of the membrane and the
electrodes will be a clear focus of the R&D work. A proof of concept prototype of
about 100 W (3 g/h H
2 equivalent) will be assembled and tested by the end of the
project for a projected lifetime of >10,000 h.