Hydrogenation behavior of the R4MgCo (R=Y, La, Nd, Tb) compounds

• Published in: Journal of solid state chemistry Vol. 229; pp. 135 - 140
• Main Authors: Shtender, V.V., Paul-Boncour, V., Riabov, A.B., Denys, R.V., Zavaliy, I.Yu
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-09-2015
• Subjects: Crystal structure; Hydrogen storage; Magnesium compounds; Metal hydride; Rare Earth compounds; Thermal desorption; Hydrogen storage; Thermal desorption; Metal hydride; Magnesium compounds; Rare Earth compounds; Crystal structure
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2015.05.024

The hydrogen absorption properties of the R4MgCo compounds (R=Y, La, Nd, Tb; str. type Gd4RhIn; sp.gr. F4¯3m) have been studied for the first time. It was shown that their hydrogen storage capacity reaches about 2wt%. At low pressure hydrogenation and moderately elevated temperatures the formed hydrides preserve the original structure of the metallic matrix. The crystal structure of the R4MgCoHx hydrides have been determined by XRD. Experimental hydrogen storage capacity (12 at.H/f.u. for Y4MgCo) is in good agreement with the theoretically calculated models, which allow also to estimate the distribution of H-atoms in metal lattice. TDS and DSC experiments demonstrated the multistep desorption process. XRD studies of the Tb4MgCoHx sample after TDS demonstrated the formation of TbH2 as the main phase and disproportionation of the parent compound.
Hydrogenation curves of R4MgCo compounds. For R=Y at 25ºC and R=La, Nd, Tb at 120ºC.
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•The hydrogenation of the R4MgCo compounds (R = Y, La, Nd, Tb) has been studied•The crystal structure of the R4MgCoHx hydrides have been determined.•Theoretical modeling of H-sublattice for the Y4MgCoH12 hydride has been calculated.•TDS and DSC experiments demonstrated the multistep desorption process for the hydrides.