Dissolution, diffusion and permeation behavior of hydrogen in vanadium: a first-principles investigation

Abstract

Employing a first-principles method, we have studied the stability, diffusivity, and permeation properties of hydrogen (H) and its isotopes in bcc vanadium (V). A single H atom is found to favor the tetrahedral interstitial site (TIS) in V. The charge density distribution exhibits a strong interaction between H and its neighbor V atoms. Analysis of DOS and Bader charge reveals that the occupation number of H-induced low energy states is directly associated with the stability of H in V. Further, H is shown to diffuse between the neighboring TISs with a diffusion barrier of 0.07 eV. Diffusion coefficients and permeabilities of H isotopes in V are estimated with empirical theory. At a typical temperature of 800 K, the diffusion coefficient and the permeability of H are 2.48 × 10(-4) cm(2) s(-1) and 2.19 × 10(-9) mol m(-1) s(-1) Pa(- 1/2), respectively.

Investigation of adsorption, dissociation, and diffusion properties of hydrogen on the V (1 0 0) surface and in the bulk: A first-principles calculation

“…The solution energy ( E sol ) of the interstitial H atom in bulk bcc V can be obtained as [9], [10], [13], [14]EsolH=ENV+H-ENV-12EH2where E N V+H and E N V are the total energies of the supercell with one H atom and no H atom, respectively. N represents the number of V atoms and E H 2 is the total energy of one H 2 molecule.…”

“…In addition, V and its alloys are not only considered important H 2 storage materials with a large H capacity [8], but also candidate materials for the first walls and blankets of fusion reactors because of their excellent low activation characteristics under neutron irradiation, remarkable high-temperature performance, and swelling resistance under neutron radiation [10]. Until now, many researchers have performed many experiments and theoretical studies on V-based permeable membrane materials, mainly concentrating on the bulk [10], [11], [12], [13], [14], [15], [16]. For instance, a work by Dolan et al showed that a Pd catalyst layer-coated 0.25 mm V substrate membrane exhibited a high permeability under H 2 permeation testing, especially at ≥320 °C, initially exceeding 3.0 × 10 −7 mol m −1 s −1 Pa −1/2 ; the thick-walled membrane was self-supporting and pinhole-free [11].…”

“…For instance, a work by Dolan et al showed that a Pd catalyst layer-coated 0.25 mm V substrate membrane exhibited a high permeability under H 2 permeation testing, especially at ≥320 °C, initially exceeding 3.0 × 10 −7 mol m −1 s −1 Pa −1/2 ; the thick-walled membrane was self-supporting and pinhole-free [11]. Luo et al [13] theorised that H atoms would preferentially occupy tetrahedral interstitial sites (TISs) for greater stability than that offered by octahedral interstitial sites (OISs) or substitutional sites; the corresponding formation energies of occupation were −0.374, −0.226, and +1.83 eV. A theory by Zhang et al [10] and first-principles exploration by Gui et al [14] of the trapping mechanism of H vacancies in solid V both showed that single H atoms preferentially occupy sites near the OIS instead of vacancy centre sites; in addition, mono-vacancy sites can trap as many as 12 H or six H 2 species.…”

Influence of Nickel Addition on the Stability, Trapping, and Diffusion Behaviour of Hydrogen in Vanadium: A First-Principles Investigation

“…Apparently, the most favourable locations for H are the interstitial sites, and our calculation results are similar to the early experimental results that stated that the heat of solution is −0.36±0.3 eV40 . In addition, the theoretical values of the solution energies reported by Luo41 after the structural relaxation processes for TIS, OIS, and SS are −0.374, −0.226, and +1.83 eV, respectively. Furthermore, our calculations showed that the formation energy of the V vacancy is +2.473 eV, which agrees with the experimental value of 2.2±0.4 eV 42 .…”

Assessment and Application of Density Functional Theory for the Prediction of Structure and Reactivity of Vanadium Complexes

“…Most previous validation or applications of DFT for vanadium are specific to vanadium metal, 19 oxides, 20−24 and/or clusters 25 and may not be well representative of the geometrical and electronic diversity in vanadium coordination chemistry. Of more significant relevance is the work of Ooms et al, 26 Justino et al, 27 and Li et al 28 on heptacoordinate hydroxylamido vanadium picolinate complexes, oxoperoxo vanadium complexes of lactic acid, and divanadocene carbonyls, respectively (though only ref 27 explicitly tests more than two model chemistries).…”