Co9 S8

Co₉S₈ is a cobalt sulfide compound belonging to the metal chalcogenide semiconductor family, characterized by a mixed-valence cobalt structure that gives it unique electronic and catalytic properties. This material has emerged primarily in electrochemistry and energy storage research, where it serves as an active catalyst for water splitting, oxygen evolution reactions, and as a component in battery electrodes; it is notable for combining earth-abundant cobalt with sulfur to achieve catalytic performance comparable to precious-metal catalysts while offering cost advantages and improved stability in alkaline environments.