Fluorine- and Nitrogen-Codoped MoS 2 with a Catalytically Active Basal Plane

Two-dimensional molybdenum disulfide (2D MoS 2 ) has drawn persistent interests as one of the most promising alternatives to Pt catalysts for the hydrogen evolution reaction (HER). It is generally accepted that the edge sites of 2D MoS 2 are catalytically active but the basal planes are inert. Activating the MoS 2 basal plane is an obvious strategy to enhance the HER activity of this material. However, few approaches have sought to activate the basal plane. Here, for the first time, we demonstrate that the inert basal planes can be activated via the synergistic effects of nitrogen and fluorine codoping. Our first-principles calculations reveal that nitrogen in the basal plane of the fluorine- and nitrogen-codoped MoS 2 (NF-MoS 2 ) can act as a new active and further tuneable catalytic site. The as-prepared NF-MoS 2 catalyst exhibited an enormously enhanced HER activity compared to that of pure MoS 2 and N-doped MoS 2 due to the chemical codoping effect. This work will pave a novel pathway for enhancing the HER activity using the synergistic effects of chemical codoping.