X-ray absorption spectroscopy (XAS) is a central technique in our quest for structure-activity relationships in water splitting. We further explored the terra incognita of highly active catalysts with both unknown motifs and completely amorphous structures. We established a comprehensive top-down & bottom-up approach that combined ex situ XAS and PDF with in situ formation monitoring of such catalysts. Our first target was a commercialized - yet structurally unknown – disordered Co-OER catalyst with oxidized dppe ligands. Its newly unraveled motif bears stunning analogy to bio-inspired systems and holds the key to high materials’ resilience (Matter 2019, 1, 1354).

In our systematic studies of Co-oxide catalysts, we demonstrated the crucial influence of detailed optimization of empirical synthesis parameter to hit the “sweet spots” of property-activity relationships.  The vast empirical parameter space to be screened for getting the most out of a given catalyst production was investigated representatively, applying microwave-hydrothermal synthesis on Co-spinel OERs (Front. Chem. 2020, 8, 473; ACS Omega 2019, 4, 15444). We currently explore the origins and influential order/disorder transitions of highly active Co-precipitates as effortless photocatalytic OER archetypes (in preparation).

Chem. Eur. J. 2018, 24, 18242