Insights into the Interfacial Lewis Acid-Base Pairs in CeO -Loaded CoS Electrocatalysts for Alkaline Hydrogen Evolution.

Despite the known efficacy of CeO as a promoter in alkaline hydrogen evolution reaction (HER), the underlying mechanism of this effect remains unclear. CoS , a pyrite-type alkaline HER electrocatalyst, suffers from sluggish HER kinetics and severe catalyst leaching due to its weak water dissociation kinetics and oxygen-related corrosion. Herein, it is demonstrated that the interfacial Lewis acid-base Ce∙∙∙S pairs in CeO -loaded CoS effectively improve the catalytic activity and durability. In CeO -loaded CoS nanowire array electrodes, these interfacial Lewis acid-base Ce∙∙∙S pairs with unique electronic and structural configurations efficiently activate water adsorptive dissociation and kinetically accelerate hydrogen evolution, delivering a low overpotential of 36 mV at 10 mA cm in alkaline media. Such Ce∙∙∙S pairs also weaken O adsorption on CoS , leading to undecayed activity over 1000 h. These findings are expected to provide guidance for the design of CeO -based electrocatalysts as well as other hybrid electrocatalysts for water splitting.