Sandwich-like Co(OH)x/Ag/Co(OH)2 nanosheet composites for oxygen evolution reaction in anion exchange membrane water electrolyzer

Abstract Development of efficient and durable materials for the oxygen evolution reaction (OER) is essential for hydrogen production via electrocatalytic water splitting. In this study, we demonstrated sandwich-like Co(OH)x/Ag/Co(OH)2 nanosheet composites as efficient OER electrocatalysts in alkaline media. The composites were fabricated on carbon paper (CP) through Ag galvanic displacement on the as-electrodeposited Co(OH)2 nanosheet layer and subsequent electrodeposition of the second Co(OH)2 nanosheet layer. Benefiting from the introduction of Ag particles and the unique sandwich structure, the resulting composites exhibited excellent OER activity with the overpotential of 283 mV at the current density of 10 mA/cm2 and Tafel slope of 97 mV/dec in a 1.0 M KOH. Furthermore, an anion exchange membrane water electrolyzer employing the composite catalyst on CP as the anode, demonstrated a high cell performance with current density of 0.6 A/cm2 at 1.8 V.