AI 中文总结
研究针对镍纳米颗粒吸氢形成氢化镍过程中氢化物生长各向异性及相关耦合效应，开发化学 - 热 - 力学焓模型，考虑多种因素及不同界面取向，能在多尺度正确预测焓和体积变化，为相关材料模型开发提供基础。
AI 中文摘要
镍纳米颗粒常用于氢化反应催化及储氢应用。近期研究表明小镍纳米颗粒能在低于 10 巴压力下吸收氢形成氢化镍，此过程中氢化物生长各向异性且形成连贯的 Ni/NiH 界面。为解释各向异性并综合考虑化学、机械和热效应的耦合，本研究为薄膜中 Ni/NiH 界面开发了简化的化学 - 热 - 力学焓模型。该模型考虑了氢化物形成程度 x、温度 T、压力 P、尺寸效应（l）以及α/β界面能λ的综合影响，研究了（100）和（111）两种不同的α/β界面取向。结果表明该模型能在从原子薄层（约 1 纳米）到微米尺度及更大尺度的广泛长度范围内正确预测焓和体积变化。此工作为其他观察到氢化物相各向异性生长的固态储氢纳米结构材料开发类似焓模型提供了基础。
英文摘要
Ni nanoparticles are frequently used as catalysts for hydrogenation reactions as well as in hydrogen storage applications. Recently, we have shown that small Ni nanoparticles can absorb hydrogen at < 10 bar pressure to form Ni hydride. During this process, the hydride growth is anisotropic, and a coherent Ni/NiH interface is formed. In order to explain the anisotropy and to comprehensively account for the coupling chemical, mechanical and thermal effects, we develop in this study a simplified chemo-thermo-mechanical enthalpy model for Ni/NiH interfaces in thin films. This model captures the combined influence of extent of hydride formation x, temperature T, pressure P, size effect ($l$), and the $α$/$β$ interface energy $λ$. Two different $α$/$β$ interface orientations, namely (100) and (111), are investigated. The model is shown to correctly predict the enthalpy and volume changes over a wide range of length scales, from atomically thin layers (~1 nm) to micron scale and larger. This work provides the basis for the development of similar enthalpy models for other solid-state hydrogen storage nanostructured materials where anisotropic growth of hydride phases is also observed.
Comments40 pages, 12 figures
