Theoretical study of CO and Pb adsorption on the Ni(111) and Ni3Al(111) surfaces

Kośmider, K.

doi:10.1016/j.apsusc.2010.01.108

Cited by 20 publications

(6 citation statements)

References 22 publications

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“…Thus having a subsurface Al neighbor strengthens the CO bonding in contrast to surface Al atoms that weaken the bonding. Similar results have been reported recently for a ͑2 ϫ 2͒-1CO structure ͑0.25 ML͒ on a Ni 3 Al͑111͒ surface 60 and a c͑2 ϫ 4͒-1CO structure ͑0.125 ML͒ on a modified Ni 3 Al͑111͒ surface, 82 with only Ni atoms in the topmost layer. It was argued that the preference for Ni-hcp compared to Ni-fcc should be attributed to the electronic structure of the sublayer atoms.…”

Section: Discussionsupporting

confidence: 90%

Adsorption of CO onNi3Al(111)investigated using high-resolution photoemission spectroscopy and density functional theory

et al. 2010

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The adsorption of CO on Ni 3 Al͑111͒ has been studied using high-resolution photoemission spectroscopy and density functional theory. Despite the fact that CO binds to Ni dominated sites only at this surface, CO adsorption induces a shifted contribution in the Al 2p core-level spectra. This contribution moves toward higher binding energy upon increasing CO coverage. The calculations give Al 2p core-level binding energy shifts in good agreement with the experimental values and show that adsorption of CO in the Ni sites induces core-level binding energy shifts for nearby Al atoms located in the two outermost surface layers. The surface Al atoms relax inward upon CO adsorption. At low CO coverage only one peak is observed in the C 1s spectra. This contribution is assigned to CO adsorbed in Ni threefold hollow sites. The calculations predict that CO adsorbs in the hollow sites for coverages up to 0.50 ML with a strong preference for the hcp site above a second layer Al atom at low coverage. At higher CO coverage, an additional contribution appears in the C 1s spectra whereas the other contribution shifts toward higher binding energies. The theoretical results suggest that this behavior is originating from the occupation of Ni on top and Ni bridge sites in addition to hollow sites.

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Section: Discussionsupporting

confidence: 90%

Adsorption of CO onNi3Al(111)investigated using high-resolution photoemission spectroscopy and density functional theory

et al. 2010

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“…The energy cutoff was set to 400 eV. In all calculations, the generalized gradient approximation (GGA) with the PW91 exchange-correction functional was utilized to solve the Kohn–Sham equation, which has been demonstrated to be capable of providing accurate descriptions on gas adsorption phenomena on metal surfaces. − We used a 3 × 3 × 1 Monkhorst-Pack k -point mesh to sample the first Brillouin zone. All calculations were carried out using the spin-polarization method since the magnetism of the systems has been found to significantly influence the adsorption energies and structures for molecular species on transition metal surfaces. , Population analysis was performed based on the Bader charge division scheme.…”

Section: Computational Model and Methodsmentioning

confidence: 99%

On the Mechanisms of Carbon Formation Reaction on Ni(111) Surface

et al. 2012

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The carbon formation reaction (abbreviated in this work from now on as CFR) is an industrially important chemical process. Using density functional theory, we explored the detailed mechanisms of the process on the Ni(111) surface. Four possible reaction pathways that give rise to carbon deposition on the surface were examined based on minimum energy path calculations. It was found that both the direct dissociation of CO on the surface and the pathway in which a gas phase H 2 molecule reacts with an adsorbed CO molecule to produce a gas phase water molecule and a C adatom are kinetically difficult due to the high activation energies. It was identified that the rate limiting step along the reaction pathway is CO* + 2H* → HCO* + H*. Comparison of the calculated energetic profiles of the CFR process on both the Ni( 111) and the γ-Fe(111) surfaces was also made. Both the H atom and the CO moiety exhibit high mobility on the surfaces after adsorption, which allows them to readily react with various surface species. We found that the Ni(111) surface is capable of blocking the sequential surface reactions in the early stages, in contrast to the surface processes on the γ-Fe(111) surface. This suggests that nickel is more resistant against carbon formation than iron, which is consistent with experimental observations.

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“…The optimized nickel lattice parameter was 3.52 Å, which is in excellent agreement with the experimental data and previous simulation results. , The Ni(111) surface was modeled with a three-layer slab of either (3 × 3) or (4 × 4) surface cells separated by a 15 Å gap in the z direction. A Mo 3 O 6 cluster supported on the (3 × 3) or (4 × 4) Ni(111) surface (MoO x /Ni(111)) was used to represent the MoO x (0 < x < 3) modified Ni catalyst .…”

Section: Computational Detailsmentioning

confidence: 99%

Theoretical Insight into Tuning CO₂ Methanation and Reverse Water Gas Shift Reactions on MoO_x-Modified Ni Catalysts

et al. 2022

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Catalytic conversion of CO2 to CO via reverse water gas shift (RWGS) and CH4 via methanation are competing reactions that simultaneously happen on Ni-based catalysts, and selective control of the reactions is of great importance to subsequent applications. Herein, conversion of CO2 on Mo3O5/Ni(111) with varying MoO x coverages was investigated using a combination of density functional theory (DFT) calculation and microkinetic modeling. The overall reaction proceeds through sequential RWGS to CO and CO methanation. The coordinatively unsaturated Mo (Moov) site at the interface of Mo3O5/Ni(111) enhances CO2 adsorption and facilitates C–O cleavage over the bare Ni(111), leading to more favorable CO2 direct dissociation to CO formation than the carboxyl and formate pathways. The oxophilic Moov also facilitates hydrogenation of CO to HCO and decomposition of CHO to CH and O. On Mo3O5/4 × 4 Ni(111), the enhanced hydrogenation and C–O breakage activity resulted in CH4 as the selective product. On Mo3O5/3 × 3 Ni(111), in contrast, the reduced size of the surface Ni ensembles caused the d-band center of surface Ni sites to shift downward, weakened CO adsorption, and reduced the hydrogenation activity, resulting in CO as the dominant product. Microkinetics analysis revealed that direct CO2 dissociation was the dominant path on Mo3O5/4 × 4 Ni(111) and the interfacial sites of Mo3O5/4 × 4 Ni(111) were primarily covered by O and OH. The rate-limiting step on Mo3O5/Ni(111) was the regeneration of Mo3O5. Consistent with the experimental results, the microkinetics also predicts that CH4 is selectively produced on Mo3O5/4 × 4 Ni(111) whereas CO is the primary product on Mo3O5/3 × 3 Ni(111).

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Theoretical study of CO and Pb adsorption on the Ni(111) and Ni3Al(111) surfaces

Cited by 20 publications

References 22 publications

Adsorption of CO onNi3Al(111)investigated using high-resolution photoemission spectroscopy and density functional theory

Adsorption of CO onNi3Al(111)investigated using high-resolution photoemission spectroscopy and density functional theory

On the Mechanisms of Carbon Formation Reaction on Ni(111) Surface

Theoretical Insight into Tuning CO₂ Methanation and Reverse Water Gas Shift Reactions on MoO_x-Modified Ni Catalysts

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Theoretical study of CO and Pb adsorption on the Ni(111) and Ni3Al(111) surfaces

Cited by 20 publications

References 22 publications

Adsorption of CO onNi3Al(111)investigated using high-resolution photoemission spectroscopy and density functional theory

Adsorption of CO onNi3Al(111)investigated using high-resolution photoemission spectroscopy and density functional theory

On the Mechanisms of Carbon Formation Reaction on Ni(111) Surface

Theoretical Insight into Tuning CO2 Methanation and Reverse Water Gas Shift Reactions on MoOx-Modified Ni Catalysts

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Theoretical Insight into Tuning CO₂ Methanation and Reverse Water Gas Shift Reactions on MoO_x-Modified Ni Catalysts