Surface structure and energetics of oxygen and CO adsorption on α-Mo2C(0001)

Elementary steps of syngas reactions on Mo2C(001): Adsorption thermochemistry and bond dissociation

“…This large discrepancy, as well as the smaller discrepancies for lattice constants and bulk modulus, are consistent with the known error trends of the RBPE functional for bulk systems [62]. Previous studies of Mo 2 C with generalized gradient functionals have resulted in lattice constants within 0.5% [45], bulk modulii within 0.1% [48], and formation energies within 9% [39] of reported experimental values. This indicates that the generalized gradient approximation provides an accurate description of the electronic structure of Mo 2 C. The RPBE functional is used for this study since it provides an improved description of the adsorption properties of surfaces [58].…”

“…The reactivity of each site was examined for carbon, hydrogen, and oxygen. Each atomic adsorbate followed a similar trend with the H C(l) site showing the highest reactivity in agreement with several previous studies [45,46,49,40]. The specific adsorption energies for carbon and oxygen are shown in Figure 1(c).…”

“…In order to further improve the performance of molybdenum carbide catalysts it is of value to understand the reactivity, selectivity, and stability of molybdenum carbide under various conditions. Numerous theoretical studies have investigated the surface stability [38,39,40,41], adsorption energies [42,43,44,45,46,47,48,49,50,51,40,52], reaction energetics [53,54,46,55,52], and alkali-doping [40,50] on Mo 2 C. The most well-studied surface is the Mo 2 C(001) surface, and both orthorhombic and hexagonal close packed Mo 2 C have been investigated. The results have indicated that the non-polar (011) surface is the most stable regardless of carbon chemical potential, but that the surface energies are sufficiently close that all surfaces are expected to be present on nanoparticles [40,39].…”

Adsorption and dissociation of H2S on Mo2C(001) surface-A first-principle study

“…Previous results for the H adsorption on this surface indicated that H adsorbs more strongly to the metal-terminated carbide surface than to the C-terminated surface [23]. Also Ren et al [29] found adsorption energies for O and CO 37 and 31% higher on Mo-terminated than on C-terminated surfaces.…”

The electronic structure and reactivity of the oxygen-modified Mo2C(0001) surface

“…On the other hand, it has been found that the peaks at 0.4, 4.1 and 5.3 eV do not show dispersions as a function of hn, and thus the initial states should be ascribed to the states localized to the oxygen-covered surface [6]. The states at 4.1 and 5.3 eVare ascribed to the O 2p-induced bonding states, which have been theoretically predicted to exist around 5 eV by Ren et al [8].…”