Theoretical Study of an almost Barrier-Free Water Dissociation on a Platinum (111) Surface Alloyed with Ruthenium and Molybdenum

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 and somewhat exothermic. The electronic structure analysis showed that much more charge was released in Mo and was used to bind the adsorbed hydroxyl (OH ad ). Further analyses of the density of states (DOS) showed that the large number of orbitals that overlap when OH binds to Mo are responsible for the stabilization of the OH-surface bond. The stability of the OH ad fragment on the surface is believed to be a descriptor for the dissociation of H 2 O with an almost spontaneous process.

Calculations of the Potential Energy Surface for a Water Molecule 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].…”

“…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)).…”

“…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.…”

Exploring the Evolution Mechanism of Sulfur Vacancies by Investigating the Role of Vacancy Defects in the Interaction between H2S and the FeS(001) 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.…”

“…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.…”