Theoretical study of the influence of Na on CO adsorption and dissociation on Pd(111): Long-range or short-range interactions between co-adsorbates?

Gan, Li‐Yong; Tian, Rong; Yang, Xiao‐Bao; Zhao, Yu-Jun

doi:10.1016/j.cplett.2011.06.002

Cited by 11 publications

(11 citation statements)

References 40 publications

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“…The barrier is 3.98 eV and the reaction energy is 2.80 eV in accord with Gan et al on Pd(111). 3 Above all, our calculation results familiarly agree well to those in previous theoretical studies.…”

Section: Comparison With Experiments and Previoussupporting

confidence: 90%

Systematic Theoretical Study of CO Activation over Clean and Potassium-Modified Transition Metals

Wang

2022

J. Phys. Chem. C

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By using the periodic density functional theory (DFT) method, the adsorption and activation of CO on clean and potassium-modified transition metals, which includes Fe(100), Co(0001), Ni(111)/(100), Cu(111), Ru(0001), Rh(111)/(100), Pd(111), and Pt(111) surfaces, have been investigated systematically. The calculation results show that the additive of potassium atoms greatly enhances the binding strength of CO and O while only slightly improving the adsorption of C atoms. Moreover, the activation energy of CO dissociation is decreased in the presence of potassium additive atoms. Our results indicate that the CO activity enhancement by the series of alkali metals (Li, Na, K, Rb, and Cs) on Ni(100) increases in the order of Li < Na < Cs < Rb = K. On the basis of the electronic structure and geometric analysis, the physical origin of the promotion effect has been clarified, and it can be attributed to the direct electron transfer between potassium and O atoms involved in CO. The effect of an external electric field on CO activation was also investigated, in which it was shown that a positive electric field accelerated CO activation by elongating the C–O bond and transferring electrons. It is obvious that CO adsorption is enhanced when the orientation of the external electric field is the same as the direction of charge transfer. At last, the promoting effect of potassium on CO activation drops as the oxide state of potassium increases due to the steric effect and direct chemical bonding.

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Section: Comparison With Experiments and Previoussupporting

confidence: 90%

Systematic Theoretical Study of CO Activation over Clean and Potassium-Modified Transition Metals

Wang

2022

J. Phys. Chem. C

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“…Similar to other AM/TM cases, i.e., Na/Pd(111), 44 after K adsorption, part of its valence electrons is transferred to the substrate without much modification of the surface band features, suggesting that the donated electrons are rather delocalized. Meanwhile, the valence bands of K were found crossing the Fermi level, indicative of the metallic nature of K adlayer.…”

Section: A K On-surface Adsorptionsupporting

confidence: 69%

Surface structure and phase transition of K adsorption on Au(111): By ab initio atomistic thermodynamics

Gan

Tian

Yang

et al. 2012

The Journal of Chemical Physics

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We studied the interactions between atomic potassium (K) and Au(111) at a range of coverage (i.e., Θ(K) = 0.11-0.5 monolayer (ML)) by ab initio atomic thermodynamics. For K on-surface adsorption, we found that K energetically favors the three-fold hollow sites (fcc or hcp), while the most significant surface rumpling was obtained at the atop sites. The incorporation of gold atoms in the adsorbate layer gradually becomes energetically favorable with increasing K coverage. We proposed a possible model with a stoichiometry of K(2)Au for the (2 × 2)-0.5 ML phase observed in lower energy electron diffraction (LEED): one K at atop site and the other K as well as one Au adatom at the second-nearest fcc/hcp and hcp/fcc, respectively. Clear theoretical evidences were given for the ionic interaction of K on Au surface. Additionally, phase transitions were predicted based on chemical potential equilibrium of K, largely in line with the earlier reported LEED observations: the clean surface → (√3 × √3)R30° → (2 × 2), and (2 × 2) → (√3 × √3)R30° reversely at an elevated temperature.

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“…The same method of adding electrons to flat surfaces have been used to explore the charge effects on the adsorption and dissociation property of CO on the Pd(111) surface. 60 The comparison results for relative parameters of such given reactions dehydrogenation on pure, K-promoted and negatively polarized Cu(111) and Cu(110) are listed in Table S4. It is found that the same change tendency for the TS structure occurs on Cu 2− (111) and Cu 2− (110) as that on K-added Cu surfaces compared with that on both pure surfaces.…”

Section: Discussionmentioning

confidence: 99%

“…To confirm this idea, we have searched the TSs of H 3 CO, H 2 O, and H 3 COH dehydrogenation and calculated the corresponding energy barriers on the negatively charged Cu(111) and Cu(110) surfaces, which are modeled by adding two additional electrons to the neutral Cu surfaces, denoted as Cu 2– (111) and Cu 2– (110). The same method of adding electrons to flat surfaces have been used to explore the charge effects on the adsorption and dissociation property of CO on the Pd(111) surface . The comparison results for relative parameters of such given reactions dehydrogenation on pure, K-promoted and negatively polarized Cu(111) and Cu(110) are listed in Table S4.…”

Section: Discussionmentioning

confidence: 99%

Effect of Potassium on Methanol Steam Reforming on the Cu(111) and Cu(110) Surfaces: A DFT Study

Wang

Zhang

et al. 2021

J. Phys. Chem. C

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The potassium (K) additive is of great importance in improving the efficiency of catalytic reactions in numerous industrial reaction processes. In this work, density functional theory calculations are carried out to investigate the reaction mechanism as well as selectivity and activity of the methanol steam reforming (MSR) reaction on pure and K-added Cu(111) and Cu(110) surfaces. Our results suggest that the K adatom can improve the selectivity of MSR toward CO 2 by stabilizing the weakly adsorbed H 2 CO species and enabling it to react with OH to yield H 2 COOH followed by continuous dehydrogenation into CO 2 and activity of MSR by favoring the rate-limiting steps for H 3 CO, H 2 O, and H 3 COH dehydrogenation. It is found that there are two key factors contributing to K promotion effects: one is the direct K−O bonding interaction that would stabilize nearly all oxygenates including H 2 CO species and the stabilized oxygenates of transition states (TSs) result in the lower dissociation barriers of key steps on both Cu surfaces; the other is the indirect interaction between K and adsorbates mediated by added surface electrons donated by K, which would affect the magnitude of interaction energies between two fragments of TSs and thus energy barriers of key steps. The fact that more electrons are donated from K to Cu(111) than to the Cu(110) surface and further to the TS complexes would result in the stronger promotion effect of K on the MSR reaction over Cu(111) compared with Cu(110). Our results emphasize the essence of the promotion effect of alkali additives on complex reaction systems.

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Theoretical study of the influence of Na on CO adsorption and dissociation on Pd(111): Long-range or short-range interactions between co-adsorbates?

Cited by 11 publications

References 40 publications

Systematic Theoretical Study of CO Activation over Clean and Potassium-Modified Transition Metals

Systematic Theoretical Study of CO Activation over Clean and Potassium-Modified Transition Metals

Surface structure and phase transition of K adsorption on Au(111): By ab initio atomistic thermodynamics

Effect of Potassium on Methanol Steam Reforming on the Cu(111) and Cu(110) Surfaces: A DFT Study

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