EFFECT OF ALLOYING ELEMENTS ON THE FORMATION OF FeTiH4: AN AB INITIO STUDY


Sen F. G. , Kinaci A., AYDINOL M. K.

ARW on Using Carbon Nanomaterials in Clean-Energy Hydrogen Systems, Crimea, Ukrayna, 22 - 28 Eylül 2007, ss.573-578 identifier

  • Basıldığı Şehir: Crimea
  • Basıldığı Ülke: Ukrayna
  • Sayfa Sayıları: ss.573-578

Özet

FeTi can store 3.7 wt% hydrogen if it is synthesized in the form of FeTiH4. In the present study, candidate alloying elements were investigated that would decrease the formation energy of this hydride, using first principles calculations within the generalized gradient approximation (GGA) to density functional theory (DFT). Selected alloying elements are Co, Mg, Mo, Ni, Nb, V and Zr, and they were substituted for Fe or Ti atoms separately. Their effects on the formation energy of FeTiH4 were analyzed on the basis of electronic structure. It was found that Zr, Nb, Mo and Mg substitution for Fe decreases the formation energy of the hydride considerably. Stabilization is achieved by forming stronger bonds between hydrogen atoms and rest of the Fe atoms in the structure which is facilitated by the antibonding between the hydrogen atoms and the substituted high tendency hydride forming element.