Amorphous TiCu-Based Additives for Improving Hydrogen Storage Properties of Magnesium Hydride

Journal Article · Fri Sep 27 00:00:00 EDT 2019 · ACS Applied Materials and Interfaces

DOI:https://doi.org/10.1021/acsami.9b16076· OSTI ID:1581992

Zhou, Chengshang  ^[1]; Bowman, Robert C. ^[2]; Fang, Zhigang Zak  ^[3]; Lu, Jun  ^[4]; Xu, Lei ^[3]; Sun, Pei ^[3]; Liu, Huang ^[1]; Wu, Hong ^[1]; Liu, Yong  ^[1]

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1. Central South Univ., Hunan (China)
2. RCB Hydrides, LLC, Franklin, OH (United States)
3. The Univ. of Utah, Salt Lake City, UT (United States)
4. Argonne National Lab. (ANL), Argonne, IL (United States)

Magnesium hydride has long been regarded as a promising candidate material for hydrogen and heat storage due to its high hydrogen capacity, reversibility, and low cost. Catalytic doping has been demonstrated as one of the most effective methods to improve hydrogen storage properties of MgH₂. In this study, amorphous Ti₄₅Cu₄₁Ni₉Zr₅ and Ti₄₀Cu₄₇Zr₁₀Sn₃ alloys are used as additives for MgH₂. Nanostructured MgH₂ doped with amorphous or crystalline TiCu-based alloys are prepared by using a high-energy mechanochemical synthesis method. Results show that the amorphous TiCu additives provide enhanced catalytic effects compared to crystalline alloys of the same composition. Doping MgH₂ using an amorphous Ti₄₅Cu₄₁Ni₉Zr₅ alloy yielded improved dehydrogenation kinetics compared to using crystalline Ti₄₀Cu₄₇Zr₁₀Sn₃ alloy. The analysis using transmission electron microscopy reveals that there are nanostructured catalytic particles uniformly distributed in the amorphous TiCu-catalyzed MgH₂. The MgH₂ system catalyzed by amorphous TiCu-based alloy shows little degradation during hydrogenation and dehydrogenation cycling at 300 °C. The amorphous TiCu-based catalysts are thermally stable at temperatures up to 360 °C. Heating the amorphous Ti₄₅Cu₄₁Ni₉Zr₅-catalyzed MgH₂ to temperatures above 360 °C led to disproportionation of the catalyst alloy and the formation of MgCu₂ and Ti₂Cu. In addition, PCI analysis of the amorphous Ti₄₅Cu₄₁Ni₉Zr₅-catalyzed MgH₂ shows a slight increase in hydrogen equilibrium pressure, resulting in a reaction enthalpy of -78.7 kJ/mol • H₂ and an entropy of 145.0 J/K•mol•H₂. As a result, the entropy calculated from this study is approximately 10 J/K•mol•H₂ higher than values previously reported for undoped and catalyzed Mg-H systems.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1581992
• Journal Information: ACS Applied Materials and Interfaces, Vol. 11, Issue 42; ISSN 1944-8244
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
08 HYDROGEN
amorphous alloy
catalyst
hydrogen storage material
kinetics
magnesium hydride