Thermodynamics of H<sub>2</sub>O Splitting and H<sub>2</sub> Formation at the Cu(110)–Water Interface

Lousada, Cláudio M.; Johansson, Adam Johannes; Korzhavyi, Pavel A.

doi:10.1021/acs.jpcc.5b01154

Cited by 32 publications

(40 citation statements)

References 99 publications

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“…Lower symmetry is often connected with decreased stability of the correspondent surface films when compared with higher symmetry structures . Recent DFT investigations have shown that for Cu(110), even though the dissociation products of H 2 O bind weaker to the surface than those originating from H 2 S, the former form higher symmetry structures than the H 2 S counterparts ,,. Because sulfide films are less protective than films of oxide – as shown in a combined DFT‐SEM‐EDX study – a connection is often made between the extent of the mismatch between the structures of the substrate‐adsorbate layer and the stability of the surface products .…”

Section: Introductionmentioning

confidence: 99%

“…[11] Recent DFT investigations have shown that for Cu(110), even though the dissociation products of H 2 O bind weaker to the surface than those originating from H 2 S, the former form higher symmetry structures than the H 2 S counterparts. [14,16,17] Because sulfide films are less protective than films of oxide [18] -as shown in a combined DFT-SEM-EDX study -a connection is often made between the extent of the mismatch between the structures of the substrate-adsorbate layer and the stability of the surface products. [13] For Cu surfaces, the origin of the more extensive reconstruction driven by sulfur species when compared to the O counterparts, lays largely in the strength of the bonding with the surface, because S binds considerably stronger than O by % 0.4 to 0.6 eV, as demonstrated by DFT computations and UPS spectra.…”

Section: Introductionmentioning

confidence: 99%

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Adsorption of Hydrogen Sulfide, Hydrosulfide and Sulfide at Cu(110) ‐ Polarizability and Cooperativity Effects. First Stages of Formation of a Sulfide Layer.

2018

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Understanding the surface site preference for single adsorbates, the interactions between adsorbates, how these interactions affect surface site specificity in adsorption and perturb the electronic states of surfaces is important for rationalizing the structure of interfaces and the growth of surface products. Herein, using density functional theory (DFT) calculations, we investigated the adsorption of H S, HS and, S onto Cu(110). The surface site specificity observed for single adsorbates can be largely affected by the presence of other adsorbates, especially S that can affect the adsorption of other species even at distances of 13 Å. The large supercell employed with a surface periodicity of (6×6) allowed us to safely use the Helmholtz method for the determination of the dipole of the surface-adsorbate complex at low adsorbate coverages. We found that the surface perturbation induced by S can be explained by the charge transfer model, H S leads to a perturbation of the surface that arises mostly from Pauli exclusion effects, whereas HS shows a mix of charge transfer and Pauli exclusion effects. These effects have a large contribution to the long range adsorbate-adsorbate interactions observed. Further support for the long range adsorbate-adsorbate interactions are the values of the adsorption energies of adsorbate pairs that are larger than the sum of the adsorption energies of the single adsorbates that constitute the pair. This happens even for large distances and thus goes beyond the H-bond contribution for the H-bond capable adsorbate pairs. Exploiting this knowledge we investigated two models for describing the first stages of growth of a layer of S-atoms at the surface: the formation of islands versus the formation of more homogeneous surface distributions of S-atoms. We found that for coverages lower than 0.5 ML the S-atoms prefer to cluster as islands that evolve to stripes along the [1 1‾ 0] direction with increasing coverage. At 0.5 ML a homogeneous distribution of S-atoms becomes more stable than the formation of stripes. For the coverage equivalent to 1 ML, the formation of two half-monolayers of S-atoms that disrupt the Cu-Cu bonds between the first and second layer is more favorable than the formation of 1 ML homogeneous coverage of S-atoms. Here the S-Cu bond distances and geometries are reminiscent of pyrite, covellite, and to some extent chalcocite. The small energy difference of ≈0.1 eV that exists between this structure and the formation of 1 ML suggests that in a real system at finite temperature both structures may coexist leading to a structure with even lower symmetry.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Adsorption of Hydrogen Sulfide, Hydrosulfide and Sulfide at Cu(110) ‐ Polarizability and Cooperativity Effects. First Stages of Formation of a Sulfide Layer.

2018

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“…Yet, as highlighted by the authors of the cited study, the kinetics and energetics of such a process are dependent on the type of surface—the crystallographic plane—as well as the presence of surface defects. In aqueous media, R2 is expected to be slower—and have an energy barrier—due to the presence of surface defects and solvation effects as well as the hindering that these pose to the encounters between surface H-atoms when compared to the solid-gas interface38. The energy barrier for R3 corresponds to the transfer of an H-atom from solution into bulk Cu.…”

Section: Discussionmentioning

confidence: 99%

“…The background samples consist of non-irradiated copper exposed to water for the same period of time as that of the irradiated samples. The background samples are necessary because copper has some amount of hydrogen from the manufacturing and even without the influence of ionizing radiation copper can induce the formation of minute amounts of H 2 (g) when exposed to water3738. This is because water can adsorb dissociatively on some copper surfaces and this process leads to the formation of both HO • and H • , the latter is a precursor of H 2 38.…”

Section: Introductionmentioning

confidence: 99%

Gamma radiation induces hydrogen absorption by copper in water

Lousada

Soroka

Yagodzinskyy

et al. 2016

Sci Rep

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One of the most intricate issues of nuclear power is the long-term safety of repositories for radioactive waste. These repositories can have an impact on future generations for a period of time orders of magnitude longer than any known civilization. Several countries have considered copper as an outer corrosion barrier for canisters containing spent nuclear fuel. Among the many processes that must be considered in the safety assessments, radiation induced processes constitute a key-component. Here we show that copper metal immersed in water uptakes considerable amounts of hydrogen when exposed to γ-radiation. Additionally we show that the amount of hydrogen absorbed by copper depends on the total dose of radiation. At a dose of 69 kGy the uptake of hydrogen by metallic copper is 7 orders of magnitude higher than when the absorption is driven by H2(g) at a pressure of 1 atm in a non-irradiated dry system. Moreover, irradiation of copper in water causes corrosion of the metal and the formation of a variety of surface cavities, nanoparticle deposits, and islands of needle-shaped crystals. Hence, radiation enhanced uptake of hydrogen by spent nuclear fuel encapsulating materials should be taken into account in the safety assessments of nuclear waste repositories.

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“…For some applications, where the system is driven out of equilibrium, the knowledge of the structure and properties of stable as well as metastable compounds is necessary for for understanding, predicting, and controlling the behavior of copper. Although Cu 2 O and CuOH have been detected as products of copper corrosion under anoxic conditions 4,[6][7][8] , some circumstances of such corrosion behavior are still unclear 9,10 .…”

Section: Introductionmentioning

confidence: 99%