Surface-Fe-doped cobalt sulfide as a highly active and stable oxygen evolution reaction catalyst for seawater splitting

The development of highly active and stable oxygen evolution reaction (OER) catalysts is crucial, yet challenging, for seawater splitting. In this study, a surface-Fe-doped cobalt sulfide OER catalyst for seawater splitting was designed and fabricated via a facile and rapid surface doping procedure. The obtained optimal catalyst exhibited a high OER performance in alkaline seawater, achieving 100 and 500 mA cm-2 at overpotentials of 0.30 and 0.37 V, respectively, and an ultra-high Faradaic efficiency (FE) of approximate 100%. In addition, the catalyst exhibited excellent stability; after 250 h of continuous operation under 100 mA cm-2 in alkaline seawater, no obvious decay in performance was observed. The high performance and stability of the catalyst demonstrates its potential for practical and commercial applications. Moreover, the developed strategy can be applied for the rational design and fabrication of OER catalysts with high activity and stability for seawater splitting.