Surface self-reconstruction by the electrochemical activation is considered as an effective strategy to increase the oxygen evolution reaction (OER) performance of transition metal compounds. Herein, uniform Co-2(OH)(3)Cl microspheres are developed and present an activation-enhanced OER performance caused by the etching of lattice Cl- after 500 cyclic voltammetry (CV) cycles. Furthermore, the OER activity of Co-2(OH)(3)Cl can be further enhanced after small amounts of Fe modification (Fe2+ as precursor). Fe doping into Co-2(OH)(3)Cl lattices can make the etching of surface lattice Cl- easier and generate more surface vacancies to absorb oxygen species. Meanwhile, small amounts of Fe modification can result in a moderate surface oxygen adsorption affinity, facilitating the activation of intermediate oxygen species. Consequently, the 10% Fe-Co-2(OH)(3)Cl exhibits a superior OER activity with a lower overpotential of 273 mV at 10 mA cm(-2) (after 500 CV cycles) along with an excellent stability as compared with commercial RuO2. (C) 2020 Elsevier Inc. All rights reserved.