Chemisorption of carbon monoxide, carbon dioxide and ¿methanephobia¿ on the [0001] titanium surface Academic Article in Scopus uri icon

abstract

  • © 2019 We performed simulations with density functional theory and molecular dynamics to investigate the interaction of CO, CO 2 , and CH 4 with the surface of a [0001] titanium slab made of four titanium layers. Our simulations were performed at atmospheric pressure and 300 K. We found that the CO molecule is chemisorbed, with dissociation at the surface with an adsorption energy of ¿3.11 eV. The CO 2 molecule can be physisorbed or chemisorbed. In physisorption, the molecule ends up at a distance from the surface of around 3.8 Å. The adsorption energy is ¿0.3157 eV. The chemisorption occurs in three possible ways. In the first, the molecule is adsorbed with no dissociation in the process, with an adsorption energy of ¿3.157 eV. In the second, the molecule is dissociated to CO and O, with an adsorption energy of ¿5.2028 eV. In the third case, the dissociation is complete, and the adsorption energy is ¿8.595 eV. We also used the nudged-elastic-band (NEB) method to calculate the chemisorption energies for this molecule, and we found very similar results. Finally, it is found that the CH 4 molecule is repelled from the surface. These calculations were performed these calculations using standard GGA, and afterwards we utilized Vdw-DF2, which includes long-range correlation effects as Van der Waals interactions. The same results are obtained. It can be said that the [0001] titanium surface presents ¿methane phobia.¿

publication date

  • June 1, 2019