First-principles analysis of the C–N bond scission of methylamineon Mo-based model catalysts

摘要

The C–N bond breaking of methylamine on clean, carbon (nitrogen, oxygen)-modified Mo(100)[denoted as Mo(100) and Mo(100)–C(N,O), respectively], Mo_2C(100), MoN(and Pt(100)surfaces has been investigated by the first-principles density functional theory (DFT) calculations.The results show that the reaction barriers of the C–N bond breaking in CH_3NH_2on Mo(100)-C(N,O) are higher than that on clean Mo(100). The calculated energy barrier can be correlatedlinearly with the density of Mo 4d states at the Fermi level after the adsorption of CH_3NH_2for thosesurfaces. Moreover, the DFT results show that the subsurface atom, e.g., carbon, can reduce thereaction barrier. In addition, We noticed that the activation energies for the C–N bond breaking onMo_2C(100) and MoN(are similar to that on Pt(100), suggesting the catalytic properties ofthe transition metal carbides and nitrides for C–N bond scission of CH_3NH_2might be very similarto the expensive Pt-group metals.