Morphological Degradation of Oxygen Evolution Reaction-Electrocatalyzing Nickel Selenides at Industrially Relevant Current Densities
Felix Hiege, Chun-Wai Chang, Oliver Trost, Charlotte E. R. van Halteren, Pouya Hosseini, Georg Bendt, Stephan Schulz, Zhenxing Feng, Julia Linnemann, Kristina Tschulik
In our new study, we were able to successfully use ultramicroelectrodes (UME) to achieve current densities in the range of industrial relevance (> 1 A cm-2) for alkaline oxygen evolution reaction (OER) without having to use the complex setup of an electrolyzer. Using electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) of the UME before and after electrochemical OER, we were also able to detect morphological changes in the nanoparticulate nickel selenide catalyst. In addition to the well-known transformation into nickel oxides/oxyhydroxides, we observed the “merging” of the granular starting particles into flat aggregates at current densities above > 1 A cm-2, which has not yet been observed in OER catalysts studied at lower current densities.