A new TiFeO hydride phase: Ti9Fe3(Ti0.7Fe0.3)O3H7

Chemical surface modification for the improvement of the hydrogenation kinetics and poisoning resistance of TiFe

“…Studies of the thin films TiFe + Pd showed that Pd coating (20 nm) of TiFe (100-200 nm thick films deposited on silicon) promotes the hydrogenation of TiFe; the rate of hydrogen uptake can be further increased by annealing of the Pd-capped TiFe in air [19]. Most probably, the reason for that is in the formation of oxygen-containing phases (Ti 4 Fe 2 O 1−x ) which were shown to easy absorb hydrogen at mild conditions [20][21][22]. The formation of such phases was also observed in the course of arc-melting of titanium, iron and iron oxide [6], or sintering of Ti and Fe powders in non-purified hydrogen (99.8% H 2 + 0.2% O 2 ), to yield TiFe as a major product [10].…”

Electronic structure of Ti4Fe2O as determined from first-principles APW + LO calculations and X-ray spectroscopy data

“…In the latter work, it was established that hydrogen capacity increased with decreasing the oxygen content y in the Ti 4−x Fe 2+x O y compounds. Hiebl et al [8] oxides with various titanium-to-iron ratios reveals the general influence of titanium substitution by iron on hydrogen capacity: it reduces due to addition of iron in the above oxides [2,8,14,15].…”

“…However, TiFe-based alloys demand the activation heating for their hydrogen sorption (e.g., about 400 • C for TiFe and Ti 1.1 Fe, 300-350 • C for Ti 1.1 Fe 0.9 Mn 0.1 , about 100 • C for Ti 1.1 Fe 0.8 Ni 0.1 Cu 0.1 [4,6,7]). The literature data [2,[8][9][10] reveal that the ternary oxygen-stabilized Ti 4−x Fe 2+x O y compounds can absorb hydrogen even at room temperature without preliminary thermal activation. It was found that other oxides in the Ti-Fe-O system, mainly Ti 3 Fe 3 O and Ti 10 Fe 7 O 3 compounds, did not absorb hydrogen at the same conditions as TiFe [11,12].…”

“…The ternary oxygen-stabilized Ti 2 Ni-type Ti 4−x Fe 2+x O y -phases (0 < x < 0.9, where y = 0.4-1.0 and y = 0.8-1.0 for titanium-reach and iron-reach alloys, respectively) have attracted considerable attention due to the possible role of these phases in the activation processes of TiFe hydrogen-storage alloys [1][2][3]. It is well known that the TiFe system and its derivative alloys are of great technological importance for energy storage [4,5].…”

Synthesis and crystal structure of -Zr9V4SH∼23

“….,1 range are formed in Ti-,Zr-,Hf-based systems and belong to the filled Ti 2 Ni (η-Fe 3 W 3 C) and filled Re 3 B-types of structure, respectively. Changing oxygen content causes variation of hydrogen absorption/desorption characteristics [1][2][3][4][5][6][7]. Several features of this behaviour should be mentioned: (1) the higher is the oxygen content the lower is the hydrogenation capacity (Ti 4 Fe 2 O x , Zr 3 V 3 O x , Zr 4 Fe 2 O x , Zr 3 Fe(Co,Ni)O x ) [1,2,[4][5][6]; (2) the redistribution of oxygen atoms in the unit cell during the hydrogenation (Zr 3 V 3 O x , Zr 3 NiO x ) [5,6] and (3) decrease of ability to disproportionation with the increase of non-metallic interstitial atoms concentration [2,7].…”