Surface modification of TiFe hydrogen storage alloy by metal-organic chemical vapour deposition of palladium

TiFe-based hydrogen storage materials are highly sensitive towards gas impurities which induce a significant deterioration of the hydrogen absorption performances. An efficient solution to this problem is in modification of the material surface by the deposition of metals (including Palladium) capable of catalyzing the dissociative chemisorption of hydrogen molecules. In this work the surface modification of TiFe alloy was performed using a metal-organic chemical vapour deposition technique (MOCVD), by the thermal decomposition of palladium (II) acetylacetonate (Pd[acac]2) mixed with the powder of the parent alloy. Such a treatment was shown to result in the formation of coatings comprised of palladium nanoparticles, which subsequently facilitate the hydrogenation of the material even after its exposure to air, which otherwise prove detrimental. However, the hydrogenation performances were found to be quite sensitive to MOCVD conditions that, most probably, originates from side processes in the interaction of gaseous products of Pd[acac]2 decomposition with TiFe.

► TiFe was surface modified by MOCVD (thermal decomposition of Pd acetylacetonate). ► The surface modification results in the formation of Pd nanoparticles. ► The deposited Pd promotes hydrogenation ability of TiFe after exposure to air. ► The hydrogenation performances are quite sensitive to MOCVD conditions.