Quantitative assessment of hydrogen diffusion by activated hopping and quantum tunneling in ordered intermetallics

Abstract

Diffusion of hydrogen in metals is a fundamental process in hydrogen storage in metal hydrides, hydrogen purification by metal membranes, and in hydrogen embrittlement. Quantitative applications of existing models for hydrogen diffusion by activated hopping and quantum tunneling require large scale first principles calculations that are not well suited to metal alloys containing many structurally distinct interstitial sites. We applied a semiclassically corrected version of harmonic transition state theory in conjunction with plane wave density functional theory to examine hydrogen diffusion in multiple C15 Laves phase AB 2 compounds and in bcc CuPd. Comparison with experimental data shows that this theory correctly captures the characteristics of hydrogen diffusion in these materials over a wide range of temperatures. This method is well suited to application in complex alloys.

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].…”

Hydrogen on and in Selected Overlayer Near-Surface Alloys and the Effect of Subsurface Hydrogen on the Reactivity of Alloy Surfaces

“…For instance, previous work has shown that certain NSAs can trap hydrogen in their subsurface [13,28,29]. Beyond the possible hydrogen storage applications of such systems, subsurface and bulk hydrogen has been identified as a reaction intermediate for several catalytic reactions on monometallic catalysts, such as alkene hydrogenation on Pd [30,31] and alkene hydrogenation and methanation on Ni [32][33][34][35]. Additionally, subsurface hydrogen has been shown to affect the binding of other species on single crystals and nanoparticles [36].…”

Ab initio study of hydrogen diffusion in zirconium oxide

“…Hydrogen diffusion behavior has recently been quantitatively evaluated by electronic state calculations [15][16][17][18][19][20]. In these calculations, hydrogen diffusion is derived from the calculated potential energy.…”