Using density functional theory to study hydrogen diffusion in metals: A brief overview

First-principles investigation of hydrogen trapping and diffusion at grain boundaries in nickel

“…This result closely agrees with results of previous calculations [34,35]. We investigated in detail the influence of quantum corrections [2,32,[34][35][36] using the semi-classically corrected transition state theory [37,38] and found that these corrections are relatively small for Ni and do not affect the results presented here. This investigation will be reported elsewhere [39].…”

Magnesium-based materials for hydrogen storage: Recent advances and future perspectives

“…Figure 5 shows that the diffusion coefficient of hydrogen within MgH 2 is in a range of 10 −18 →10 24 m 2 /s at 300-100℃ and the activation energy for hydrogen diffusion in Mg hydrides can be easily calculated to be 107.9 kJ/mol. This value agrees well with data in a recent review by Sholl [82] . Using the data derived from this model, the effect of grain size on hydrogenation rate can be calculated as shown in Figure 6.…”

“…The diffusivity of hydrogen atoms within MgH 2 and the formation rate of MgH 2 on the Mg surface and/or along the grain boundaries (if any) are the key factors for hydrogenation capacity and kinetics. This is because the diffusion coefficient in MgH 2 is much smaller than that in Mg, such as, ~10 −18 compared to ~10 −8 m 2 /s at 300℃ [82,83] . Before the shell of MgH 2 formed around the Mg surface, the hydrogen atoms diffuse very fast in Mg, after which hydrogen diffusion becomes very slow and it is very difficult for hydrogen atoms to penetrate through the shell of MgH 2 .…”

Pd-Alloy membranes for hydrogen separation

“…Permeability is a composite property that depends on both hydrogen solubility and diffusivity (Eq. (4)), each of which can vary independently as functions of alloy composition, alloy structure, and operating conditions [11][12][13][14].…”