Bifunctional Amorphous Transition‐Metal Phospho‐Boride Electrocatalysts for Selective Alkaline Seawater Splitting at a Current Density of 2A cm−2

Hydrogen production by direct seawater electrolysis is an alternative technology to conventional freshwater electrolysis, mainly owing to the vast abundance of seawater reserves on earth. However, the lack of robust, active, and selective electrocatalysts that can withstand the harsh and corrosive saline conditions of seawater greatly hinders its industrial viability. Herein, a series of amorphous transition-metal phospho-borides, namely Co-P-B, Ni-P-B, and Fe-P-B are prepared by simple chemical reduction method and screened for overall alkaline seawater electrolysis. Co-P-B is found to be the best of the lot, requiring low overpotentials of ≈270 mV for hydrogen evolution reaction (HER), ≈410 mV for oxygen evolution reaction (OER), and an overall voltage of 2.50 V to reach a current density of 2 A cm