Abstract:A theoretical study
based on density functional theory for H
2
O dissociation
on the metal surface of Pt(111) alloyed simultaneously
with Ru and Mo was performed. The determination of the minimum energy
path using the climbing image nudged elastic band (CI-NEB) method
shows that the dissociation reaction of H
2
O with this catalyst
requires almost no energy cost. This dissociation reaction is not
only kinetically favored but also almost thermodynamically neutral
an… Show more
“…In our previous results from Ref. [35,36], the H2O adsorb aligned parallel with Pt(111) and the distance of O−Pt [re(O−Pt)]=2.31 Å, the ∠ (H1−O−H2) angle broadening to 105.7° and the adsorption energy was about −0.30 eV. This results are near to the results from Fajin et al [37].…”
Section: Resultssupporting
confidence: 75%
“…The co-adsorption of (OHads+Hads)/Pt(111) configuration was also obtained from cf., e.g., [35,36] and references therein as a (FS) configuration. The separated H2' at hollow fcc site position from OH1 is far enough to ensure that H2' already broken from its water configuration (presented in figure 1(c)).…”
Section: Resultsmentioning
confidence: 99%
“…To simulate the adsorption of a H2O and co-adsorption of OHads +Hads on the Pt(111), we use our previous results from Ref. [35,36] for initial state [IS] and final state [FS] configurations as presented in figure 1(b) and 1(c) respectively. Based on figure 1, we describe the dissociation pathways using potential energy surfaces (PESs) scan by separating the H2 atom into H2' position varies in terms of the shortest possible path on Pt (111) while OH1 being attached on top site of Pt43.…”
We present a density functional theory (DFT) study of the dissociation pathway of monomeric H2O into adsorbed hydroxyl (OHads) and hydrogen (Hads) on the Pt(111) surface. Here we consider the Langmuir-Hinshelwood process of adsorbed monomeric H2O, which is then dissociated on the surface model. By calculating potential energy surfaces (PESs), we examine the proposed pathways to determine the most likely ones. The results show that the activation energies of two reaction pathways are comparable within the experimental and theoretical results. This study should provide information to understand the mechanism of H2O dissociation on the Pt(111) surface.
“…In our previous results from Ref. [35,36], the H2O adsorb aligned parallel with Pt(111) and the distance of O−Pt [re(O−Pt)]=2.31 Å, the ∠ (H1−O−H2) angle broadening to 105.7° and the adsorption energy was about −0.30 eV. This results are near to the results from Fajin et al [37].…”
Section: Resultssupporting
confidence: 75%
“…The co-adsorption of (OHads+Hads)/Pt(111) configuration was also obtained from cf., e.g., [35,36] and references therein as a (FS) configuration. The separated H2' at hollow fcc site position from OH1 is far enough to ensure that H2' already broken from its water configuration (presented in figure 1(c)).…”
Section: Resultsmentioning
confidence: 99%
“…To simulate the adsorption of a H2O and co-adsorption of OHads +Hads on the Pt(111), we use our previous results from Ref. [35,36] for initial state [IS] and final state [FS] configurations as presented in figure 1(b) and 1(c) respectively. Based on figure 1, we describe the dissociation pathways using potential energy surfaces (PESs) scan by separating the H2 atom into H2' position varies in terms of the shortest possible path on Pt (111) while OH1 being attached on top site of Pt43.…”
We present a density functional theory (DFT) study of the dissociation pathway of monomeric H2O into adsorbed hydroxyl (OHads) and hydrogen (Hads) on the Pt(111) surface. Here we consider the Langmuir-Hinshelwood process of adsorbed monomeric H2O, which is then dissociated on the surface model. By calculating potential energy surfaces (PESs), we examine the proposed pathways to determine the most likely ones. The results show that the activation energies of two reaction pathways are comparable within the experimental and theoretical results. This study should provide information to understand the mechanism of H2O dissociation on the Pt(111) surface.
“…As shown in Figure S1a, the slab model of the FeS(001) surface adopts a 2 × 2 supercell structure and is equipped with nine atomic layers to adapt to the relaxation expansion of the first layer. An additional 15 Å vacuum layer is placed to ensure separation. , Zero-point energy (ZPE) correction is performed for the adsorption energy and dissociation energy barriers. , In all calculations involving the interaction of H 2 S and the dissociated atoms with the FeS(001) surface, the adsorbate and top three layers of atoms are totally allowed to relax, while the remaining atomic layers are fixed.…”
Section: Computational Detailsmentioning
confidence: 99%
“…37,38 Zero-point energy (ZPE) correction is performed for the adsorption energy and dissociation energy barriers. 39,40 In all calculations involving the interaction of H 2 S and the dissociated atoms with the FeS(001) surface, the adsorbate and top three layers of atoms are totally allowed to relax, while the remaining atomic layers are fixed.…”
Vacancy defects are
inherent point defects in materials. In this
study, we investigate the role of Fe vacancy (VFe) and
S vacancy (VS) in the interaction (adsorption, dissociation,
and diffusion) between H2S and the FeS(001) surface using
the dispersion-corrected density functional theory (DFT-D2) method.
VFe promotes the dissociation of H2S but slightly
hinders the dissociation of HS. Compared with the perfect surface
(2.08 and 1.15 eV), the dissociation energy barrier of H2S is reduced to 1.56 eV, and HS is increased to 1.25 eV. Meanwhile,
S vacancy (VS) significantly facilitates the adsorption
and dissociation of H2S, which not only reduces the dissociation
energy barriers of H2S and HS to 0.07 and 0.11 eV, respectively,
but also changes the dissociation process of H2S from an
endothermic process to a spontaneous exothermic one. Furthermore,
VFe can promote the hydrogen (H) diffusion process from
the surface into the matrix and reduce the energy barrier of the rate-limiting
step from 1.12 to 0.26 eV. But it is very hard for H atoms gathered
around VS to diffuse into the matrix, especially the energy
barrier of the rate-limiting step increases to 1.89 eV. Finally, we
propose that VS on the FeS(001) surface is intensely difficult
to form and exist in the actual environment through the calculation
results.
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