Crystallinity-dependent structural evolution of CoS2 catalysts for enhanced oxygen evolution reaction

catalysts with varying crystallinities and their effect on the OER. In-situ characterization and density functional theory (DFT) calculations reveal that lower crystallinity enables rapid equilibrium among surface sulfur-oxygen exchange, metal site activation, and oxygen intermediate evolution, enhancing the transformation of bulk phase into small amounts of sulfur-stabilized oxyhydroxide and improving OER performance. Conversely, moderate crystallinity leads to self-corrosion and progressive structure collapse from the exterior inward, resulting in deactivation. This work highlights the potential of crystallinity control in optimizing the electronic states and catalytic behavior of water oxidation catalysts.