Figure 6: Catalysis mechanism of inner Pt nanoparticles.

(a) CO stripping and (b) Cu UPD of 40 wt% Pt/C and Pt-MoS2, showing the different accessibility of inner Pt nanoparticles. (c) The saturation rate of the Cu monolayer deposition upon holding at a fixed UPD potential, which indicates a much slower diffusion process in the case of Pt-MoS2 compared with Pt/C. (d) Schematics showing the anisotropic diffusion of CO gas and cupric ions into Pt-MoS2.