Abstract:
The effect of modifying V
2C using transition metals (TMs) (Ti, Ni, Zr, and Nb) on the MgH
2 dehydrogenation properties was investigated using the density functional theory (DFT). The adsorption energy, dehydrogenation energy, and electronic structure of MgH
2 on TM (Ti, Ni, Zr, and Nb)@V
2C were calculated. The results showed that TM atoms tended to occupy the face-centered cubic sites of V
2C. MgH
2 adsorption on V
2C was improved by adding a TM and the order of the adsorption energy was as follows: Ni@V
2C > Ti@V
2C > Zr@V
2C > Nb@V
2C > V
2C. An orbital hybridization peak between H and TM atoms was observed in the electronic structure of MgH
2 on TM (Ti, Ni, Zr, and Nb)@V
2C. The addition of a TM supported on V
2C substantially improved the dehydrogenation energy of (MgH
2)
4 clusters, and the order of improvement was Ni@V
2C > Ti@V
2C > Nb@V
2C > Zr@V
2C. The dehydrogenation energy of (MgH
2)
4 clusters on Ni@V
2C was lower than that of pure (MgH
2)
4 clusters and (MgH
2)
4 clusters on V
2C, by 1.60 and 1.11 eV, respectively. TM@V
2C combinations had significantly enhanced MgH
2 dehydrogenation, providing theoretical justification for conducting experiments to develop novel high-performance catalysts.
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