Prototype of a photoelektrochemical cell for hydrogen production. Photo: Hereon
The solar hydrogen production by photo-induced water splitting has a high potential to protect existing resources and to increase the share of renewable energies. The conversion of renewable energy into chemical energy in the form of hydrogen provides an efficient storage technology that can compensate fluctuations in energy production and energy consumption.
The department Multifunctional interfaces is therefore pursuing the work with the following objectives:
- Development of inexpensively manufacturable photoelectrochemically active surfaces for water splitting
- Increase of light yield for the production of hydrogen by means of optimization of the surface morphology and the chemical composition of the surfaces
- Development of cost-efficient and more effective components for the photocatalytic hydrogen production in the future
- Development of plasmonic materials and dielectrics to form optical metamaterials (in collaboration with Hamburg University of Technology (TUHH), Prof. Dr. Eich)
Principle of photocatalytic water splitting. Grafphic: Hereon
Despite the great need for a technical realization of photoelectrochemical hydrogen production so far only the basic feasibility has been demonstrated in the laboratory. On an industrial scale, it is not yet possible to develop efficiently working cells. A thorough understanding as a basis for systematic development is missing.
In the department of "Multifunctional interfaces" innovative techniques for fabrication of large area photoelectrodes are evaluated. In close cooperation with the Helmut-Schmidt-University, Hamburg, in particular the use of cold gas spraying for the production of electrodes is being tested. An important step towards enhancing the efficiency is an optimal structuring of the surface. Methods for structuring of the electrode surfaces from the nano to micro range are developed at the Hereon.
Different electrodes manufactured with the CGS process (TiO2, Hematite, BiVO4). Photo: Hereon
For a commercially simple and economical fabrication of large area photoelectrodes it is necessary to transfer semiconductor powders TiO2, WO3, Hämatit (α-Fe2O3)) to an efficiently working electrode structure.
Surface topography CGS electrodes. Photo: Hereon
One of the main factors that determine the efficiency of the catalyst is the surface area availability for the catalytic water splitting. Our department is therefore working with structured electrodes that feature a much higher surface area compared to flat electrodes. We employ novel techniques for this structuring at different scales.