TY - JOUR
T1 - Hydrogen Flux through Size Selected Pd Nanoparticles into Underlying Mg Nanofilms
AU - Kumar, Sushant
AU - Pavloudis, Theodore
AU - Singh, Vidyadhar
AU - Nguyen, Hoa
AU - Steinhauer, Stephan
AU - Pursell, Christopher
AU - Clemens, Bruce
AU - Kioseoglou, Joseph
AU - Grammatikopoulos, Panagiotis
AU - Sowwan, Mukhles
N1 - Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2018/2/5
Y1 - 2018/2/5
N2 - The application of Mg for hydrogen storage is hindered due to the slow absorption of hydrogen in Mg films. Herein, the hydrogenation process is explored theoretically using density functional theory calculations, and energy barriers are compared for hydrogen diffusion through Pd nanoparticle/Mg film interfaces and their variations, i.e., Pd(H)/Mg(O). Decomposing the mechanism into basic steps, it is shown that Pd undergoes a strain-induced crystallographic phase transformation near the interface, and indicated that hydrogen saturation of Pd nanoparticles enhances their efficiency as nanoportals. Using energetic arguments, it is explained why hydrogen diffusion is practically prohibited through native Mg oxide and seriously suppressed through existing hydride domains. Hydrogen flux is experimentally investigated through the nanoportals in Pd-nanoparticle decorated Mg films by pressure-composition isotherm measurements. An r ≈ t1/3 relationship is theoretically calculated for the radial growth of hemispherical hydride domains, and this relationship is confirmed by atomic force microscopy. The diffusion constant of hydrogen in Mg films is estimated as DHfilm ≈ 8 × 10−18 m2 s−1, based on transmission electron microscopy characterization. The unique nanoportal configuration allows direct measurement of hydride domain sizes, thus forming a model system for the experimental investigation of hydrogenation in any material.
AB - The application of Mg for hydrogen storage is hindered due to the slow absorption of hydrogen in Mg films. Herein, the hydrogenation process is explored theoretically using density functional theory calculations, and energy barriers are compared for hydrogen diffusion through Pd nanoparticle/Mg film interfaces and their variations, i.e., Pd(H)/Mg(O). Decomposing the mechanism into basic steps, it is shown that Pd undergoes a strain-induced crystallographic phase transformation near the interface, and indicated that hydrogen saturation of Pd nanoparticles enhances their efficiency as nanoportals. Using energetic arguments, it is explained why hydrogen diffusion is practically prohibited through native Mg oxide and seriously suppressed through existing hydride domains. Hydrogen flux is experimentally investigated through the nanoportals in Pd-nanoparticle decorated Mg films by pressure-composition isotherm measurements. An r ≈ t1/3 relationship is theoretically calculated for the radial growth of hemispherical hydride domains, and this relationship is confirmed by atomic force microscopy. The diffusion constant of hydrogen in Mg films is estimated as DHfilm ≈ 8 × 10−18 m2 s−1, based on transmission electron microscopy characterization. The unique nanoportal configuration allows direct measurement of hydride domain sizes, thus forming a model system for the experimental investigation of hydrogenation in any material.
KW - Pd nanoparticles
KW - cluster beam deposition
KW - density functional theory
KW - diffusion coefficient
KW - hydrogen storage
UR - http://www.scopus.com/inward/record.url?scp=85030221199&partnerID=8YFLogxK
U2 - 10.1002/aenm.201701326
DO - 10.1002/aenm.201701326
M3 - 文章
AN - SCOPUS:85030221199
SN - 1614-6832
VL - 8
JO - Advanced Energy Materials
JF - Advanced Energy Materials
IS - 4
M1 - 1701326
ER -
