科研之友
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摘要
In Part I, the cyclic stabilities of the kinetics of catalyzed MgH2 systems including MgH2-TiH2, MgH2-TiMn2, and MgH2-VTiCr were investigated, showing stable kinetics at 300 degrees C but deteriorations of the hydrogenation kinetics at temperatures below 150 degrees C. The present Part II describes the characterization of uncycled and cycled catalyzed MgH2 by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analysis. XRD analysis shows the crystallite sizes of the Mg and MgH2 significantly increased after the cycling. The mean crystallite sizes of the catalysts (TiH2 and VTiCr) increased moderately after the cycling. SEM and TEM imaging were used to compare the microstructures of uncycled (as-milled) and cycled materials, revealing a drastic change of the microstructure after 100 cycles. In particular, results from energy-dispersive spectroscopy (EDS) mapping show that a change of distribution of the catalyst particles in the Mg and MgH2 phase occurred during the cycling.
- 出版日期2015-10-1
