The factors affecting the diffusion properties of hydrogen in palladium copper alloys: Ab initio study
The factors affecting the diffusion properties of hydrogen in palladium copper alloys: Ab initio study
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影响钯铜合金中氢扩散性能的因素：从头算研究
DOI：
10.1016/j.ijhydene.2022.06.077
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发表时间：
2022-06
影响因子：
7.2
通讯作者：
Yu-Wei You
中科院分区：
文献类型：
--
作者：
Tao Wang;Pan Dong;Jie Li;Yu-Wei You
实验表明，钯（Pd）膜中加入铜（Cu）降低了氢(H)在钯中的渗透率，且H在体心立方（BCC） PdCu合金中的渗透率大于面心立方（FCC） PdCu合金中的渗透率。其根本原因仍未得到很好的理解。本文采用系统的从头计算方法研究了H在PdCu合金中扩散性能的影响因素。结果表明，H在BCC PdCu合金中的最低扩散势垒为0.016 eV，而FCC PdCu合金中的最低扩散势垒为0.346 eV。在BCC PdCu合金中，H原子间的相互作用具有明显的排斥性，而在FCC PdCu合金中，H原子间的相互作用具有吸引力。结果表明，FCC PdCu合金比BCC PdCu合金更有利于形成间隙H团簇。间隙H团簇的形成阻碍了H在FCC PdCu合金中的快速移动。FCC PdCu合金中固有空位的存在进一步阻碍了H的迁移，发现FCC PdCu合金中空位与H的结合强度远大于BCC PdCu。H与空位结合越强，对H在PdCu合金中运动的阻碍越大。这些结果阐明了FCC PdCu合金中H渗透能力弱于BCC PdCu合金的实验现象。•BCC PdCu合金比FCC PdCu合金更有利于形成间隙H原子团簇。•FCC PdCu合金的空位结合强度远大于BCC PdCu。•在BCC和FCC PdCu合金中，Cu空位对H原子捕获的影响更为明显。
The experiments showed that the addition of copper (Cu) in palladium (Pd) membrane reduces the permeability of hydrogen (H) in Pd, and the permeability of H in body-centered cubic (BCC) PdCu alloy is larger than that in face-centered cubic (FCC) PdCu alloy. The underlying reasons are still not well understood. In the present work, systematical ab initio calculations are carried out to investigate the factors affecting the diffusion properties of H in PdCu alloys. It is found that the lowest diffusion barrier of H with zero-point energy correction in BCC PdCu alloy (0.016 eV) is relatively low than that in FCC PdCu alloy (0.346 eV). The interactions among interstitial H atoms are significantly repulsive in BCC PdCu alloy, while it is attractive in FCC PdCu alloy. The results suggest that it is energetically favorable to form interstitial H cluster in FCC PdCu alloy rather than that in BCC PdCu alloy. The formation of interstitial H clusters impedes the fast movement of H in FCC PdCu alloy. The presence of intrinsic vacancy in FCC PdCu alloy further hinders the migration of H. It is found that the binding strength of vacancy with H in FCC PdCu alloy is much larger than that in BCC PdCu. The stronger the combination of H and vacancy, the greater the obstacle to the movement of H in PdCu alloy. All these results elucidate the experimental phenomena why H penetration ability in FCC PdCu alloy is weaker than that in BCC PdCu alloy. • It is energetically favorable to form interstitial H atoms cluster in BCC PdCu alloy rather than that in FCC PdCu alloy. • The binding strength of vacancy in FCC PdCu alloy is much larger than that in BCC PdCu. • The effects of Cu vacancy on trapping H atoms are more obvious in both BCC and FCC PdCu alloys.