Thermodynamic Property Study of Nanostructured Mg‐H, Mg‐Ni‐H, and Mg‐Cu‐H Systems by High Pressure DSC Method

Abstract

Mg, Ni, and Cu nanoparticles were synthesized by hydrogen plasma metal reaction method. Preparation of Mg2Ni and Mg2Cu alloys from these Mg, Ni, and Cu nanoparticles has been successfully achieved in convenient conditions. High pressure differential scanning calorimetry (DSC) technique in hydrogen atmosphere was applied to study the synthesis and thermodynamic properties of the hydrogen absorption/desorption processes of nanostructured Mg-H, Mg-Ni-H, and Mg-Cu-H systems. Van’t Hoff equation of Mg-Ni-H system as well as formation enthalpy and entropy of Mg2NiH4was obtained by high pressure DSC method. The results agree with the ones by pressure-composition isotherm (PCT) methods in our previous work and the ones in literature.

Magnesium-based hydrogen storage compounds: A review

“…Additionally, it has been proved that the Mg-Cu-H nanoparticle system possesses modified thermodynamics: the hydrogenation enthalpy and entropy are improved to be -67.5 kJ (mol -1 H2) and -124.4 J (K -1 mol -1 H2), respectively. [64] When the concentration of Mg in the alloy exceeds the normal composition corresponding to Mg2Cu, the PCI curve of this Mg-Mg2Cu alloy exhibits two plateaus and enhanced hydrogen storage properties, which closely resembles the Mg-Mg2Ni…”

Recent advances on the thermal destabilization of Mg-based hydrogen storage materials

“…Advanced research has shown that Mg-Cu-H nanoparticle systems can further reduce the hydride formation enthalpy and entropy to À67.5 kJ (mol À1 H 2 ) and À124.4 J (K À1 mol À1 H 2 ), respectively. 34 Thus from the above research, we can preliminarily conclude that nanostructuring of Mg-based alloys provides a potential strategy to further alter their thermodynamic properties without loss in their hydrogen capacity.…”

Synthesis, Morphology, and Hydrogen Absorption Properties of TiVMn and TiCrMn Nanoalloys with a FCC Structure

“…In Figure 5 , we can see that the TiVMn and TiCrMn nanoalloys may show hydrogen absorption (exothermic reaction peaks) before 450°C without any activation process. According to our experiences in study of hydrogen storage alloys for DSC measurements under hydrogen atmosphere, especially for metastable alloys without any phase transfer process in the measurement temperature range, exothermic peaks are attributed to hydrogen absorption reactions [ 44 – 46 , 51 , 52 ]. The hydrogenation peak temperatures under 1 MPa hydrogen are 412 and 375°C for the TiVMn and TiCrMn nanoalloys, respectively.…”