Updating the sub-nanometric cognition of reconstructed oxyhydroxide active phase for water oxidation

Unveiling structure-activity correlations at the sub-nanoscale remains an essential challenge in catalysis science. During electrocatalysis, dynamic structural evolution drives the ambiguous entanglement of crystals and electrons degrees of freedom that obscure the activity origin. Here, we track the structural evolution of Ni-based model pre-catalysts (Ni(OH)2, NiS2, NiSe2, NiTe), detailing their catalytically active state during water oxidation via operando techniques and theoretical calculations. We reveal the sub-nanometric structural difference of NiO6 unit with a regular distortion in the reconstructed active phase NiOOH, codetermined by the geometric (bond lengths) and electronic (covalency) structure…