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

Abstract

The C-N bond breaking of methylamine on clean, carbon ͑nitrogen, oxygen͒-modified Mo͑100͒ ͓denoted as Mo͑100͒ and Mo͑100͒-C͑N,O͒, respectively͔, Mo 2 C͑100͒, MoN͑100͒, and Pt͑100͒ surfaces has been investigated by the first-principles density functional theory ͑DFT͒ calculations. The results show that the reaction barriers of the C-N bond breaking in CH 3 NH 2 on Mo͑100͒-C͑N,O͒ are higher than that on clean Mo͑100͒. The calculated energy barrier can be correlated linearly with the density of Mo 4d states at the Fermi level after the adsorption of CH 3 NH 2 for those surfaces. Moreover, the DFT results show that the subsurface atom, e.g., carbon, can reduce the reaction barrier. In addition, We noticed that the activation energies for the C-N bond breaking on Mo 2 C͑100͒ and MoN͑100͒ are similar to that on Pt͑100͒, suggesting that the catalytic properties of the transition metal carbides and nitrides for C-N bond scission of CH 3 NH 2 might be very similar to the expensive Pt-group metals.

Adsorption and decomposition of methylamine on a Pt(100) surface: a density functional theory study

“…Although massive amounts of information involving the decomposition of methylamine have been provided through experimental investigation, the detailed catalytic decomposition mechanisms of methylamine are still not clear. Recently, theoretical investigations have been applied to reveal the adsorption congurations of possible species involved in methylamine decomposition and the relevant reactions on transition metal surfaces, such as Si, 23,24 Ni, 25,26 Mo, 27,28 Pd, 29 Ru, 30 Co, 31 and Pt 32 surfaces, and on a B 12 N 12 nanocage. 33 On Si(100), Kato et al 24 found that N-H bond scission is preferential to C-N bond scission for methylamine decomposition under milder conditions, because of the charge transfer from the surface to the N atom, which weakens the N-H bond.…”

“…The C-H bond is the easiest to split on Ni(111) and Ni(100), and the breaking of the N-H bond is most preferred on stepped Ni(111) and N-Ni(100). On a Mo(100) surface, Lv et al 27 investigated the effects of different modiers on the reactivity of Mo through the C-N bond cleavage of methylamine to form methyl and amino species. They found that the presence of C, N, and O atoms on the surface reduces the reactivity of the Mo surface.…”

Decomposition of methylamine on nitrogen atom modified Mo(100): a density functional theory study

“…Theoretical investigation related to methylamine decomposition is rather scarce. We only find theoretical investigations of methylamine on silicon, 17,18 nickel 19,20 and molybdenum 21 surfaces. N-H and C-N bond cleavages were investigated on Si(100) surface 18 theoretically, and they concluded that the N-H bond scission is preferential to C-N bond scission under milder conditions, due to the charge transfer from the surface to the N atom, weakening the N-H bond.…”

“…The C-N bond breaking shows the highest barrier on the four surfaces, and C-H bond breaking exhibits the lowest barrier on Ni(111) and Ni(100), whereas N-H bond breaking has the lowest barrier on stepped Ni(111) and N-Ni(100). In our previous work, 21 we studied the effect of different modifiers on the reactivity of molybdenum through the C-N bond cleavage of methylamine forming methyl and amino. The results show that the presence of modification atoms reduced the reactivity of Mo surface.…”

The Mechanism of Low‐Temperature CO Oxidation on IB Group Metals and Metal Oxides

“…One of the possible reasons could be the strain effect of surface metal caused by the presence of subsurface oxygen in the M 2 O(100)-M system. [45,46] Interestingly, it is found that the dband width also correlates well with the d-band center (Figure 4 a), which shows that the wider the d-band width, the further the d-band center away from the Fermi energy level.…”