Highly efficient electrocatalytic seawater splitting to produce hydrogen with an amorphous medium-entropy oxide electrocatalyst (Co0·40Ni0·30Mo0.17Re0.13)O.

Electrocatalytic seawater splitting represents a highly promising sustainable technique for hydrogen production. There exists an urgent imperative to develop cost-effective and highly active electrocatalysts for the electrocatalytic hydrogen evolution reaction (HER) from seawater. Herein, we have designed and synthesized a novel amorphous medium-entropy oxide electrocatalyst, (Co 0·40 Ni 0·30 Mo 0.17 Re 0.13)O. The amorphous structure furnishes abundant active sites, while the distinguish electronic configuration of medium-entropy oxide bestows high electrocatalytic activity upon (Co 0·40 Ni 0·30 Mo 0.17 Re 0.13)O. Density functional theory calculations and electrochemical measurements have demonstrated the superior electrocatalytic activity of the amorphous (Co 0·40 Ni 0·30 Mo 0.17 Re 0.13)O electrocatalyst towards HER. Overpotentials of only 33 and 265 mV are required to achieve a current density of 10 mA cm−2 in 1 M KOH and natural seawater, respectively. Moreover, the (Co 0·40 Ni 0·30 Mo 0.17 Re 0.13)O electrocatalyst exhibits exceptional stability. This study presents a cost-effective and highly active electrocatalyst with great potential for seawater hydrogen production and provides insights into enhancing catalyst activity through deliberate composition and structural design. [Display omitted] • A novel amorphous medium-entropy oxide (Co 0·40 Ni 0·30 Mo 0.17 Re 0.13)O electrocatalyst. • DFT calculation reveals the strong H 2 O adsorption capacity and moderate ΔG H*. • Overpotentials of 33 and 265 mV @ 10 mA/cm2 for HER in 1 M KOH and natural seawater. [ABSTRACT FROM AUTHOR]