Hydrogen is widely seen as the fuel of the future. That's because it has great energy potential and does not create exhaust emissions.
«One day, water will become a combustible fuel,» wrote Jules Verne long ago in his novel «The Mysterious Island.» What was once science fiction has become reality now in the early 21st century. A Greek research laboratory, working with its international partners, is producing hydrogen from the sun and water - or, more precisely, from steam, with the help of solar energy.
The program is called Hydrosol and researchers from the Laboratory of Aerosol and Particle Technology (LAPT) at the Center for Research and Technology Hellas (CERTH) earlier this month won the European Commission's Descartes award for research this year.
That success and recognition mean a great deal to the Greek team, even though they are used to distinctions, having won other international awards in Japan and France.
How it works
What did the Hydrosol program achieve? «We created the first solar hydrogen-producing reactor in the world and showed that it can operate continuously,» Hydrosol coordinator Thanassis Constantopoulos told Kathimerini.
How does it work? A catalytic converter made of many tubes coated with a layer of oxide-reducing nano-particles retains oxygen. When steam passes through this ceramic sponge, the oxygen is retained and pure hydrogen is produced, without any exhaust emissions.
Heat is needed for the first reaction and is collected from the sun by a system of reflectors.
At some point the catalytic converter blocks up and cannot hold back any more oxygen. Then it is chemically reactivated, which requires greater heat, up to 1,000 Celsius, which also comes from the inexhaustible source of the sun.
«So as not to interrupt the process, two such monolith reactors are placed side by side. When one of them is producing hydrogen, the other is being prepared,» explained Constantopoulos.
The Hydrosol team's innovations were to create ultra-effective nano-materials that can absorb oxygen and to make the reactor from monolithic fire-resistant material with a high capacity for absorbing solar energy.
The Greek team worked with experts from Germany (they have a solar oven, which Greece does not), Swiss specialists who made the ceramic material and Britons who made the catalytic converter.
What are the uses of solar hydrogen? «First of all in the chemicals industry, in fuel cells for the cars of the future, as an energy storage area, and even in today's internal combustions,» said Constantopoulos.
«The economy of hydrogen is the future. There is a trend away from dependence on coal. From that we turn to oil, then to natural gas and now to hydrogen. However, the vital thing is not to extract hydrogen from mineral fuels but from renewable sources of energy, and solar energy has immense potential,» he added.