1. Isothermal hydrogen production behavior and kinetics of bulk eutectic Mg–Ni-based alloys in NaCl solution
- Author
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Yanxiong Fang, Yuan-e Yang, and Wei Tan
- Subjects
Arrhenius equation ,Yield (engineering) ,Materials science ,Scanning electron microscope ,Mechanical Engineering ,Alloy ,Metals and Alloys ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Isothermal process ,0104 chemical sciences ,symbols.namesake ,Chemical engineering ,Mechanics of Materials ,Materials Chemistry ,symbols ,engineering ,Lamellar structure ,0210 nano-technology ,Eutectic system - Abstract
To seek bulk Mg-based alloys with excellence H2 production properties, smelted eutectic Mg–Ni-based alloys are successfully prepared by metallurgical method. The phase compositions and microstructures are tested by X-ray diffraction (XRD) and scanning electron microscope (SEM). The isothermal H2 production curves of prepared alloys in 3.5 wt% NaCl solution are collected at different temperatures by drainage method. H2 production kinetics and thermodynamics are investigated in combination with the microstructures results and fitting results of hydrolysis curves by Avrami-Erofeev equation and Arrhenius equation. The production capacity for Mg-23.5 wt%Ni (Mg23.5Ni) eutectic alloy is 706 mL g−1 with 0.92 conversion yield at 303 K. When 10 wt% La added, the production capacity and yield of Mg-23.5 wt%Ni-10 wt%La (Mg23.5Ni10La) are 679 mL g−1 and 0.98, respectively. The initial rate and final capacity for H2 production of experimental Mg–Ni-based eutectic alloys improve gradually with the rising reaction temperature. The hydrolysis apparent activation energies for Mg23.5Ni and Mg23.5Ni10La alloys are 40.56 kJ/mol and 31.72 kJ/mol, respectively. The refined lamellar microstructure and the introduced La2Mg17 active phase strongly promote the H2 production process of Mg23.5Ni10La alloy. The reported results provide promising way to synthesize bulk Mg-based H2 production alloys with high yield and rapid rate by controlling the microstructure and hydrolysis reaction.
- Published
- 2020
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