Triggering basal plane active sites of monolayer MoS2 for the hydrogen evolution reaction by phosphorus doping

Monolayer MoS2 has attracted much attention due to its catalytic performance in water splitting. However, the low electronic conductivity and limited number of active catalytic sites of monolayer MoS2 limit the hydrogen production efficiency. In this work, the effect of phosphorus doping on the electronic characteristics and catalytic activity of the hydrogen evolution reaction in monolayer MoS2 was studied using density functional theory. A semiconductor to conductor transformation occurs in monolayer MoS2(1-x)Px for x larger than 0.25. The Gibbs free energy is greatly reduced from 2.18 to 0.03 eV for the adsorption of hydrogen on monolayer MoS0.5P0.75. The Gibbs free energy for hydrogen atom adsorption on monolayer MoS0.5P0.75 is between 0.03 and 0.16 eV with hydrogen coverage θH = 1/12–7/12 ML. The Gibbs free energy is close to zero, indicating that phosphorus doping can trigger the basal plane active sites on monolayer MoS2; thus, this work provides a new design for the improvement of the catalytic activity of two-dimensional transition metal dichalcogenide-based catalysts by phosphorus doping.