Herein, we effectively modulate the electronic structure of Co3Fe layered double hydroxides (LDHs) by F-doping using a CHF3-plasma etching technique. CHF3-plasma can selectively fill oxygen vacancies with F− ions that can drastically tune the electronic structure with the highest electronegativity and create metal vacancies at the same time. The as-obtained F-Co3Fe LDH ultrathin nanosheets exhibit excellent oxygen evolution reaction (OER) properties. The outstanding electrochemical activity can be attributed to the incorporation of F− ions that strongly modulate the charge distribution of surrounding atoms to facilitate the adsorption of OER intermediates. This work provides a simple way to create metal vacancies and selectively fill oxygen vacancies with fluorine at the same time, and brings about a deep understanding of the electronic environment-activity relationship of LDHs for the OER.
