"Our cell consists of two different parts – a photoelectric part on top and an electrochemical part below", says Georg Brunauer. "In the upper layer, ultraviolet light creates free charge carriers, just like in a standard solar cell." The electrons in this layer are immediately removed and travel to the bottom layer of the electrochemical cell. Once there, these electrons are used to ionize oxygen to negative oxygen ions, which can then travel through a membrane in the electrochemical part of the cell.
"This is the crucial photoelectrochemical step, which we hope will lead to the possibility of splitting water and producing hydrogen", says Brunauer. In its first evolution step, the cell works as a UV-light driven oxygen pump. It yields an open-current voltage of up to 920 millivolts at a temperature of 400°C.
The photoelectrochemical cell has now been presented in the journal Advanced Functional Materials
, but the research project continues. "We want to understand the origin of these effects by carrying out a few more experiments, and we hope that we will be able to improve our materials even further", says Brunauer. If the electrical power can be increased a slightly, the cell will be able to split water into oxygen and hydrogen. "This goal is within reach, now that we have shown that the cell is working", says Georg Brunauer. The concept is not only useful for the production of hydrogen, as it could also split carbon dioxide into carbon monoxide. The produced energy carried in the form of hydrogen and carbon monoxide can be used to synthesize fuels.Source