Operando diffuse reflectance UV-vis spectroelectrochemistry for investigating oxygen evolution electrocatalysts
The characterization of the active structure of water splitting catalysts is crucial to evolve to a sustainable energy future based on hydrogen. Such an information can only be obtained by operando methods. We present a diffuse reflectance UV-Vis (DRUV) spectroelectrochemical study that allows to track the changes of solid oxygen evolution catalysts under working conditions. The versatility of our approach is demonstrated on two cobalt-containing catalysts Zn0.35Co0.65O and CoAl2O4. The changes the catalysts undergo during the oxygen evolution reaction can be tracked by probing the electronic structure by UV-Vis spectroscopy. These findings are compared to ex situ analyses, which support the assignments of the structures stabilized under different potentials. Thus, structure-activity correlations can be proposed, and deeper insights into the catalytically active structures can be obtained.