Deactivation of titanium during temperature-induced hydrogen absorption–desorption cycling

Performance Improvement of V–Fe–Cr–Ti Solid State Hydrogen Storage Materials in Impure Hydrogen Gas

“…For Ti, the highest factors of enrichment are observed for NaOH concentrations of 8 and 9 mol/L. Ti and V are known to be strongly corroded upon contact with gaseous oxygen, and the resulting surface metal oxides considerably hinder hydrogen diffusion into the bulk. , − Hence, the leaching procedure was optimized primarily with respect to the selective removal of these elements. In Table S5, the variation of the leaching temperature is shown.…”

“…However, it is likely that Ti atoms diffuse from the bulk of the material toward the surface and are enriched as a result of two combined driving forces: on the one hand, it is known that Ti–Ti bonds and bonds between Ti and other metals are relatively weak which facilitates diffusion of Ti atoms within alloys. On the other hand, the gain in free energy for the formation of TiO 2 from Ti and O 2 and thus the driving force for Ti oxidation is rather high (TiO 2 = −850 kJ·mol –1 O 2 ;V 2 O 5 = −550 kJ·mol –1 O 2 ;Cr 2 O 3 = −700 kJ·mol –1 O 2 ) . Therefore, it is likely that the combination of Ti diffusion from bulk to surface and the strong affinity of Ti to oxygen are responsible for the higher relative concentration of Ti at the surface in spite of the selective dissolution of this element in the electrolyte.…”

Thermochemical Energy Storage through De/Hydrogenation of Organic Liquids: Reactions of Organic Liquids on Metal Hydrides

“…The surfaces of vanadium and titanium are known to be sensitive even toward low concentrations of impurities. Hydrogen absorption of titanium is known to be inhibited through carbon deposition and the formation of titanium carbide even after cycling in hydrogen containing minor amounts of hydrocarbons . The formation of Ti carbohydride was observed, which is believed to be responsible for the deterioration of the hydrogen uptake kinetics …”

“…For the implementation of metal hydrides in the thermal energy storage process described above, it is essential to know the effects of methylcyclohexane and even more of toluene on metal hydrides and the reactions taking place during contact, as the hydrogen extracted from the product of the dehydrogenation step may contain small amounts of these chemical compounds. While gaseous hydrocarbons such as methane and ethane are known to be innocuous to the AB 5 -type intermetallic hydride LaNi 5 , hydrogen absorption by pure metallic titanium is known to be inhibited by propane. , To the best of our knowledge, the effect of toluene has not been systematically studied yet. One of the aims of this work is to clarify whether toluene contact affects the hydrogen sorption properties of intermetallic hydrides and to investigate the chemical reactions occurring between metal hydride and toluene.…”