Adsorption of Hexacyclic C₆H₆, C₆H₈, C₆H₁₀, and C₆H₁₂ on a Mo-Terminated α‑Mo₂C (0001) Surface

Density functional theory (DFT) calculations were performed for the adsorption of hexacyclic C₆H₆, C₆H₈, C₆H₁₀, and C₆H₁₂ molecules/radicals on the Mo-terminated α-Mo₂C (100) surface. A cluster model, Mo₃₈C₁₉, was used to simulate the finite surface of an ultradispersed α-Mo₂C catalyst. On adsorption, benzene retains a flat geometry, predominantly on the 3-fold hollow sites with 30 degree orientation between the C–C bond of benzene and the Mo–Mo bond of the catalyst. C₆H₈ also sits flat on the surface, binding strongly with it. However, the stabilization energy shows that it is unstable on the surface and tends to be further hydrogenated or decomposes before desorption. C₆H₁₀, on the contrary, binds less strongly to the surface but shows a relatively higher stability on the surface. C₆H₁₂ binds very loosely with the surface but showed high stability, indicating a high preference for desorption.