Theoretical study of methane reforming on molybdenum carbide

The adsorption of methane and the subsequent reaction of two dissociatively adsorbed CH 3 species on a β-Mo 2C (0 0 1) slab to form either ethylene or ethane were studied using density functional theory (DFT) calculations. Four methane-adsorption models of β-Mo 2C (0 0 1) with different methane adsorption profiles were investigated. Following structural optimization for adsorption, methane was dissociated into CH 3 and H at the three-fold site for the surface Mo atoms, without the underlying carbon atoms of the second layer and the two-fold site position for the surface Mo atoms before optimization. For the two adsorption positions, the adsorption energy of methane was identical at 289 kJ/mol. The other two adsorption positions were unstable relative to these two positions. After optimization of the two methanes for dissociation into 2CH 3 and 2H, with one CH 3 approaching the another CH 3, C 2H 5 (Intermediate 2) was formed, together with the formation of ethylene through the release of one hydrogen. The first principle molecular dynamics (MD) of Intermediate 2 produced ethylene with one hydrogen, while the MD of Intermediate 2 with the addition of two hydrogen molecules produced ethane following the restricted attack of one hydrogen on the C 2H 5 species at approximately 2 Å from the surface after its desorption. ▪ The adsorption of methane and the subsequent reaction of two dissociatively adsorbed CH 3 species on a β-Mo 2C (0 0 1) slab to form either ethylene or ethane were studied using density functional theory (DFT) calculations. Four methane-adsorption models of β-Mo 2C (0 0 1) with different methane adsorption profiles were investigated. Following structural optimization for adsorption, methane was dissociated into CH 3 and H at the three-fold site for the surface Mo atoms, without the underlying carbon atoms of the second layer and the two-fold site position for the surface Mo atoms before optimization. For the two adsorption positions, the adsorption energy of methane was identical at 289 kJ/mol. The other two adsorption positions were unstable relative to these two positions. After optimization of the two methanes for dissociation into 2CH 3 and 2H, with one CH 3 approaching the another CH 3, C 2H 5 (Intermediate 2) was formed, together with the formation of ethylene through the release of one hydrogen. The first principle molecular dynamics (MD) of Intermediate 2 produced ethylene with one hydrogen, while the MD of Intermediate 2 with the addit