Chemical Stability of High-Entropy Spinel in a High-Pressure Pure Hydrogen Atmosphere
oleh: Kamil Domaradzki, Anna Adamczyk, Michał Pyzalski, Tomasz Brylewski, Marek Nowak, Mieczysław Jurczyk
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2024-07-01 |
Deskripsi
This paper focuses on high-entropy spinels, which represent a rapidly growing group of materials with physicochemical properties that make them suitable for hydrogen energy applications. The influence of high-pressure pure hydrogen on the chemical stability of three high-entropy oxide (HEO) sinter samples with a spinel structure was investigated. Multicomponent HEO samples were obtained via mechanochemical synthesis (MS) combined with high-temperature thermal treatment. Performing the free sintering procedure on powders after MS at 1000 °C for 3 h in air enabled achieving single-phase (Cr<sub>0.2</sub>Fe<sub>0.2</sub>Mg<sub>0.2</sub>Mn<sub>0.2</sub>Ni<sub>0.2</sub>)<sub>3</sub>O<sub>4</sub> and (Cu<sub>0.2</sub>Fe<sub>0.2</sub>Mg<sub>0.2</sub>Ni<sub>0.2</sub>Ti<sub>0.2</sub>)<sub>3</sub>O<sub>4</sub> powders with a spinel structure, and in the case of (Cu<sub>0.2</sub>Fe<sub>0.2</sub>Mg<sub>0.2</sub>Ti<sub>0.2</sub>Zn<sub>0.2</sub>)<sub>3</sub>O<sub>4</sub>, a spinel phase in the amount of 95 wt.% was achieved. A decrease in spinel phase crystallite size and an increase in lattice strains were established in the synthesized spinel powders. The hydrogenation of the synthesized samples in a high-pressure hydrogen atmosphere was investigated using Sievert’s technique. The results of XRD, SEM, and EDS investigations clearly showed that pure hydrogen at temperatures of up to 250 °C and a pressure of up to 40 bar did not significantly impact the structure and microstructure of the (Cr<sub>0.2</sub>Fe<sub>0.2</sub>Mg<sub>0.2</sub>Mn<sub>0.2</sub>Ni<sub>0.2</sub>)<sub>3</sub>O<sub>4</sub> ceramic, which demonstrates its potential for application in hydrogen technologies.