Figure 7.

(a) Calculated free-energy diagram for HER for the hydrogenase model, the nitrogenase model, MoS₂, and metal-surface (Au, Pt, Ni, and Mo) catalysts at a potential U = 0 relative to the standard hydrogen electrode (SHE) at pH 0. Reproduced with permission from ref (186). Copyright 2005 American Chemical Society. (B) Two-dimensional representation of MoS₂ catalyst electrocatalytic active surface area and projected geometric surface area. Reproduced with permission from ref (157). Copyright 2014 American Chemical Society