Kwawu, CR;
Tia, R;
Adei, E;
Dzade, NY;
Catlow, CRA;
De Leeuw, NH;
(2017)
CO2 activation and dissociation on the low miller index surfaces of pure and Ni-coated iron metal: a DFT study.
Physical Chemistry Chemical Physics
, 19
(29)
pp. 19478-19486.
10.1039/c7cp03466k.
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Abstract
We have used spin polarized density functional theory calculations to perform extensive mechanistic studies of CO2dissociation into CO and O on the clean Fe(100), (110) and (111) surfaces and on the same surfaces coated by a monolayer of nickel. CO2chemisorbs on all three bare facets and binds more strongly to the stepped (111) surface than on the open flat (100) and close-packed (110) surfaces, with adsorption energies of -88.7 kJ mol-1, -70.8 kJ mol-1and -116.8 kJ mol-1on the (100), (110) and (111) facets, respectively. Compared to the bare Fe surfaces, we found weaker binding of the CO2molecules on the Ni-deposited surfaces, where the adsorption energies are calculated at +47.2 kJ mol-1, -29.5 kJ mol-1and -65.0 kJ mol-1on the Ni-deposited (100), (110) and (111) facets respectively. We have also investigated the thermodynamics and activation energies for CO2dissociation into CO and O on the bare and Ni-deposited surfaces. Generally, we found that the dissociative adsorption states are thermodynamically preferred over molecular adsorption, with the dissociation most favoured thermodynamically on the close-packed (110) facet. The trends in activation energy barriers were observed to follow that of the trends in surface work functions; consequently, the increased surface work functions observed on the Ni-deposited surfaces resulted in increased dissociation barriers and vice versa. These results suggest that measures to lower the surface work function will kinetically promote the dissociation of CO2into CO and O, although the instability of the activated CO2on the Ni-covered surfaces will probably result in CO2desorption from the nickel-doped iron surfaces, as is also seen on the Fe(110) surface.
| Type: | Article |
|---|---|
| Title: | CO2 activation and dissociation on the low miller index surfaces of pure and Ni-coated iron metal: a DFT study |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1039/c7cp03466k |
| Publisher version: | https://doi.org/10.1039/c7cp03466k |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10065207 |
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