Artificial Photosynthesis - Photoelectrochemistry

In natural photosynthesis plants use solar energy to convert carbon dioxide and water to carbohydrates. Photosynthesis could thus solves one of mankinds largest challenges, the long-term storage of renewable energy (in form of chemical bonds). Artificial photosynthesis aims at mimicking the basic energy conversion processes in plants, by using an inorganic device which allows for a substantially higher efficiency than its natural complement. One approach is the photoelectrochemical production of hydrogen from water or the production of carbon based fuels via photoelectrochemical CO2 reduction reaction. An efficient photoelectrochemical device has the potential to become a cornerstone of an energy economy solely based on renewable energies.

In our research we try to identify suitable surface modifications of Si- or GaP-based photoelectrodes for efficient hydrogen evolution or CO2 reduction reaction via electrocatalysis. The modifications investigated fall into two main categories: (I) the functionalization with covalently bound organic layers, and (II) a large-area surface patterning with metal nanostructure arrays. In parallel, we are interested in the reaction mechanisms of CO2 reduction reaction regarding its different products. Beside of electrocatalytic and optical characterization, we are also able to characterize our functionalized surfaces with advanced surface science tools (AFM, XPS, EC-STM, ATR-FTIR) and examine the selectivity of CO2 reduction reaction using sophisticated product analysis methods (on-line GC, HPLC, DEMS).