Through the HYDROSOL Project, the Consortium team has proposed and developed for the first time an innovative structured solar reactor for the production of hydrogen from the splitting of steam using solar energy.
The solar reactor contained no moving parts and was constructed from special refractory ceramic thin-wall, multi-channeled (honeycomb) monoliths optimized to absorb solar radiation and develop sufficiently high temperatures. The monolith channels were coated with an active water-splitting material, and the overall reactor was very similar to the familiar catalytic converter of modern automobiles. When steam passed through the solar reactor, the active coating material split water vapor by “trapping” its oxygen and leaving in the effluent gas stream as product hydrogen. In a subsequent step, the oxygen “trapping” material was regenerated (i.e. released the oxygen absorbed), by increasing the amount of solar heat absorbed by the reactor and hence a cyclic operation was established. Active oxygen “trapping”/water-splitting materials (based on doped oxides exhibiting redox behavior) had been synthesized employing different techniques.
A solar reactor (3kWth) based on ceramic refractory honeycomb structures coated with the redox materials above, has been constructed and its capability of achieving uniform temperatures of the order of 1300 °C has been demonstrated.
The evaluation of the redox materials on the solar reactor proved for the first time the feasibility of solar hydrogen production by the HYDROSOL process and the stability of the redox/support- assemblies: multi-cyclic solar thermo-chemical splitting of water was successfully demonstrated: the reactor produced hydrogen by cyclic operation exclusively at the expense of solar energy; up to 40 cycles of constant H2 production were operated in a row in a two-day continuous production of hydrogen.
Title of Programme
The 5th Framework Programme
Energy, Environment and Sustainable Development 
Energy Sub-Programme
Financing Code for Project
Project start year - end year 2002 - 2005
Financing organisation
Coordinator Aerosol and Particle Technology Laboratory (APTL)

Laboratory of Inorganic Materials CERTH-CPERI (LIM)

Deutsches Zentrum Fuer Luft - Und Raumfahrt EV (DLR)

Stobbe Tech Ceramics

Budget  2,660,000 €