Characterization of Cobalt Sulfide Catalysts

Transition metal sulfides are an important class of materials known for their structural variety along with technologically significant electronic and catalytic properties [1]. Cobalt sulfides have been investigated as oxygen-reduction catalyst and have the highest activity among all chalcogenides of nonprecious metals [2-3]. However, the phase diagram of cobalt sulfide is relatively complex containing several phases including Co 4 S 3 , Co 9 S 8 , CoS, Co 3 S 4 , Co 2 S 3 , and CoS 2 phases making analysis of samples with mixed cobalt sulfides phases challenging [1]. A commercial cobalt-sulfide catalyst was investigated in this study using scanning transmission electron microscopy (