Fluorine- and Nitrogen-Codoped MoS2 with a Catalytically Active Basal Plane

Two-dimensional molybdenum disulfide (2D MoS2) 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 MoS2 are catalytically active but the basal planes are inert. Activating the MoS2 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 MoS2 (NF-MoS2) can act as a new active and further tuneable catalytic site. The as-prepared NF-MoS2 catalyst exhibited an enormously enhanced HER activity compared to that of pure MoS2 and N-doped MoS2 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.