Strongly electrophilic heteroatoms confined in atomic CoOOH nanosheets realizing efficient electrocatalytic water oxidation

Abstract

Developing active and durable oxygen evolution reaction (OER) electrocatalysts is greatly desired for worldwide renewable energy applications. Here, via an efficient electrophilic extraction of local electrons in cobalt oxyhydroxide (CoOOH) nanosheets realized by confining high-valence transition-metal ions (Mn⁴⁺) in cation sites of the basal plane, we significantly facilitate the proton–electron transfer kinetics and reduce the charge transfer resistance by more than 50% for high-efficiency water oxidation. The as-synthesized Mn-doped CoOOH nanosheets exhibit an excellent OER performance with a quite low overpotential of 255 mV at 10 mA cm⁻² and a small Tafel slope of ∼38 mV dec⁻¹. X-ray absorption spectroscopy and first-principles calculations demonstrate that the high-valence Mn⁴⁺ ion with an unpaired 3d³ configuration extracts local electrons from Co active sites and reduces the adsorption free energy of OH by 0.7 eV for efficient oxygen evolution.