Nanosized or nanoconfined hydrides are promising materials for solid-state hydrogen storage. Most of these hydrides, however, degrade fast during the structural characterization utilizing transmission electron microscopy (TEM) upon the irradiation with the imaging electron beam due to radiolysis. We use ball-milled MgH2 as a reference material for in-situ TEM experiments under low-dose conditions to study and quantitatively understand the electron beam-induced dehydrogenation. For this, valence electron energy loss spectroscopy (VEELS) measurements are conducted in a monochromated FEI Titan3 80–300 microscope. From observing the plasmonic absorptions it is found that MgH2 successively converts into Mg upon electron irradiation. The temporal evolution of the spectra is analyzed quantitatively to determine the thickness-dependent, characteristic electron doses for electron energies of both 80 and 300 keV. The measured electron doses can be quantitatively explained by the inelastic scattering of the incident high-energy electrons by the MgH2 plasmon. The obtained insights are also relevant for the TEM characterization of other hydrides.

中文翻译：

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电子束诱导的MgH ₂脱氢的VEELS研究

纳米级或纳米级氢化物是用于固态氢存储的有前途的材料。然而，这些氢化物中的大多数在由于放射分解而在用成像电子束照射时在利用透射电子显微镜（TEM）进行结构表征期间迅速降解。我们使用球磨MgH2作为低剂量条件下原位TEM实验的参考材料，以研究和定量了解电子束诱导的脱氢作用。为此，在单色FEI Titan3 80–300显微镜中进行价电子能量损失谱（VEELS）测量。通过观察等离子体吸收，发现MgH 2在电子辐照下相继转化为Mg。对光谱的时间演变进行定量分析，以确定与厚度有关的，80 keV和300 keV的电子能量的特征电子剂量。可以通过MgH2等离子体激元对入射的高能电子进行非弹性散射来定量解释所测得的电子剂量。获得的见解也与其他氢化物的TEM表征有关。