In-situ evolution of bulk-active γ-CoOOH with immobilized Gd dopants enabling an efficient oxygen evolution electrocatalysis

Abstract

Promoting the in-situ reconstruction of transition metal (TM)-based precatalysts into low-crystalline and well-modified TM (oxy)hydroxides (TMOxHy) during alkaline oxygen evolution reaction (OER) is crucial for enhancing their catalytic performances. In this study, we incorporated gadolinium (Gd) into the cobalt hydroxide precatalyst, achieving a deep reconstruction into cobalt oxyhydroxide (γ-CoOOH) while retaining incorporated Gd during the activation process of alkaline OER. The unconventional non-leaching Gd dopants endow the γ-CoOOH with reduced crystallinity, increasing the exposure of electrolyte-accessible Co atoms and enhancing bulk activity. Furthermore, modulation of the electronic structure of γ-CoOOH substantially boosts the intrinsic activity of the active Co sites. As a result, when supported on nickel foam, the catalyst exhibits remarkable alkaline OER performance, attaining a current density of 100 mA cm−2 at a low overpotential of approximately 327 mV. Notably, an ultrahigh current density of 1000 mA cm−2 is robustly maintained for 5 days, highlighting its immense potential for practical applications in large-scale hydrogen production.