Metalų hidridų susidarymo sferinėse struktūrose plėtra ir detali skaitmeninė hidrinimo proceso analizė

Abstract

Hydrogen's distinctive features render it a viable energy carrier that can substitute fossil fuels. However, a pressing necessity persists to create safe and practical storage solutions before their extensive implementation. In this context, metal hydrides have gained increasing interest as hydrogen storage materials due to their potential to attain high volumetric energy densities, hence mitigating costs and safety concerns. The wide variations in thermodynamic characteristics across different material classes render them exceptionally adaptable. Three-dimensional spherical metal hydrides present a promising avenue due to their distinctive properties, especially the elevated surface area and volume-to-surface ratio they can achieve. The characteristics render spherical structures exceptionally suitable for compact and reversible hydrogen storage, positioning them as significant contenders for applications such as fuel cells, portable energy devices, and renewable energy storage. This study investigates the structural and chemical modifications occurring in titanium (Ti) and zirconium (Zr) thin coatings on aluminium hydroxide (AlO3) granules before and after hydrogenation. The materials undergo hydrogenation at 400 °C and 5 atm of hydrogen pressure for 2 hours, with a hydrogen flow rate of 0.8 L/min. SEM studies revealed notable morphological alterations, such as surface roughening, grain boundary separation, and microcrack formation, signifying the generation of metal hydrides. EDS analysis indicated a reduction in Ti and Zr concentration during hydrogenation, presumably attributable to hydride production. XRD studies verified the existence of hydride phases, with shifts in diffraction peaks signifying structural alterations induced by hydrogen absorption. FTIR analysis indicated dihydroxylation, which is characterised by eliminating surface hydroxyl groups and establishing new metal–hydride bonds, corroborating the structural modifications. The emergence of additional peaks in the 1100–1200 cm-1 range indicates metal hydride production, suggesting hydrogen incorporation. Mathematical modelling utilising the experimental values was conducted to assess hydride production and hydrogen diffusion rates. The hydride conversion rates for Ti- and Zr-coated AlO3 granules were 3.5% and 1.6%, respectively. The hydrogen penetration depths for Ti- and Zr-coated AlO3 granules after 2 hours were approximately 1200 nm and 850 nm, respectively. These findings align with the experimental data. This study highlights the impact of hydrogenation on the microstructure and chemical composition of Ti- and Zrcoated AlO3, offering insights into prospective uses in hydrogen storage and associated domains.