Understanding Electrochemical Water Splitting

Water electrolysis has the potential to become the major technology for the production of the high amount of green hydrogen that is necessary for its widespread application in a decarbonized economy. The bottleneck of this electrochemical reaction is the anodic partial reaction, the oxygen evolution reaction (OER), which is sluggish and hence requires efficient catalysts. We use electrochemical in situ spectroscopy techniques to study this reaction in detail.

Materials based on earth-abundant first row transition metals such as Co, Mn, Fe, Ni are widely studied as low-price catalytic materials for OER on an industrial scale application. Our work aims at an in-depth understanding of the catalytic mechanisms as well as on degradation mechanisms that occur on these electrodes to guide the knowledge-based material design. We employ operando Raman spectroscopy and spectroscopic ellipsometry to study OER catalysts on metallic substrates, to understand phase transitions dissolution processes occurring during OER, which is a generic problem for their widespread application. In the current project porous Ni based electrodes are studied under elevated current and temperature conditions that are more relevant for industrial alkaline water electrolysis. In parallel, operando surface enhanced Raman spectroscopy (SERS) and infrared spectroscopy (SEIRAS) are used to study thin catalyst films which can yield structural information about the catalytic active centers and intermediates.