MgH2–ZrN Composites for Hydrogen Generation by Hydrolysis

• Published in: Powder metallurgy and metal ceramics Vol. 60; no. 11-12; pp. 698 - 705
• Main Authors: Zavaliy, I. Yu, Berezovets, V. V., Kytsya, A. R., Solonin, Yu. M., Kordan, V. M.
• Format: Journal Article
• Language: English
• Published: New York Springer US 2022; Springer Nature B.V
• Subjects: Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composite Materials; Composites; Conversion; Glass; Hydrogen; Hydrogen production; Hydrolysis; Magnesium chloride; Materials Science; Mathematical analysis; Metallic Materials; Nanocomposites; Nanostructure; Natural Materials; Phase composition; X ray powder diffraction; Zirconium nitrides; hydrolysis; magnesium composite; hydrogen generation
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1007/s11106-022-00281-1

Nanostructured MgH 2 –ZrN composites with different zirconium nitride contents were produced by mechanical grinding in hydrogen. The phase composition of the composites was studied by X-ray powder diffraction. Traces of unreacted magnesium were found in the composites with 5 and 15 wt.% zirconium nitride. Scanning electron microscopy revealed that increase in the ZrN content led to MgH 2 refinement. The hydrogen generation by hydrolysis of the synthesized nanostructured MgH 2 –ZrN composites was studied. The hydrolysis kinetics was examined in pseudoisothermal conditions by measuring the displaced water volume. The optimal composition that promoted the maximum specific velocities and volume of hydrogen released was MgH 2 –10 wt.% ZrN. The kinetic features peculiar to hydrolysis of the MgH 2 –10 wt.% ZrN nanocomposite in MgCl 2 solutions were studied. When MgCl 2 content increased from 0 to 50 mmol/l, the degree of conversion became twice as high. A further increase in the MgCl 2 content to 100 mmol/l led only to a 3% increase in the conversion. 500 ml H 2 in pure water and 990 ml H 2 in MgCl 2 solution were generated for 90 min by hydrolysis from 1 g of the MgH 2 –10 wt.% ZrN composite. The activation parameters for hydrolysis of this nanocomposite material in water were calculated. The activation energies of freshly prepared and passivated MgH 2 were close: 44 ± 4 and 49 ± 7 kJ/mol, respectively. The degree of conversion increased from 26 to 63% when temperature raised from 40 to 60°C.