High-Entropy Borate as an Active Electrocatalyst for Boosted Alkaline Seawater Oxidation

Developing efficient and stable electrocatalysts for seawater oxidation at high current density still remains challenging due to chlorine evolution reaction at the anode. Herein, we report the facile synthesis of amorphous high-entropy borate by the chemical reduction method and identify it as a very active and robust electrocatalyst for freshwater oxidation as well as seawater oxidation. The developed high-entropy borate needs only 275 and 288 mV overpotentials in 1 M KOH and 1 M KOH + seawater, respectively, to achieve a high current density of 100 mA cm–2 and exhibits outstanding stability at such a high current density for over 50 h in alkaline real seawater.