Spherical Co/Co9S8 as electrocatalyst for hydrogen production from alkaline solution and alkaline seawater

Cobalt-based sulfide catalysts are considered as potential materials for electrocatalytic hydrogen production from seawater. Here, we have successfully prepared a Co/Co9S8 electrocatalyst with hollow spherical structure. As-prepared material exhibited excellent electrocatalytic activity in hydrogen evolution reaction (HER) in alkaline seawater. The overpotentials for Co/Co9S8 in alkaline seawater were measured as low as 136.2 mV, when reached a current density of 10 mA cm− 2. It also had good stability and could be maintained for 24 h in 1.0 M KOH and alkaline seawater. The results of SEM and TEM confirmed that the catalyst had excellent reaction structure. Due to the hollow structure, Co/Co9S8 showed remarkable catalytic performance for HER. The construction method of Co/Co9S8 hollow structure is an effective strategy to improve the performance of HER for seawater splitting.