Boosting the oxygen evolution electrocatalysis of high-entropy hydroxides by high-valence nickel species regulation

Abstract

The addition of an extra metal source induces the transformation from crystalline α-Ni(OH)₂ to an amorphous NiCoFeCrMo-based high-entropy hydroxide (HEH) and maximizes the high-valence Ni³⁺ content in HEH. For OER electrocatalysis, the quinary HEH possesses an overpotential of 292 mV at 10 mA cm⁻², a Tafel slope of 54.31 mV dec⁻¹ and the boosted intrinsic activity, surpassing other subsystems.