摘要
First-principles calculations were used to study the energetics and electronic structures of Ni and Sc co-doped MgH<sub>2</sub> system. The preferential positions for dopants were determined by the minimal total electronic energy. The results of formation enthalpy indicate that Ni and Sc co-doped MgH<sub>2</sub> system is more stable than Ni single-doped system. The hydrogen desorption enthalpies of these two hydrides are investigated. Ni and Sc co-doping can improve the dehydrogenation properties of MgH<sub>2</sub>. The lowest hydrogen desorption enthalpy of 0.30 eV appears in co-doped system, which is significantly lower than that of Ni doping. The electronic structure analysis illustrates that the hybridization of dopants with Mg and H atom together weakens the Mg-H interaction. And the Mg-H bonds are more susceptible to dissociate by Ni and Sc co-doping because of the reduced magnitude of Mg-H hybridization peaks. These behaviors effectively improve the dehydrogenation properties of Ni and Sc co-doped cases.
First-principles calculations were used to study the energetics and electronic structures of Ni and Sc co-doped MgH<sub>2</sub> system. The preferential positions for dopants were determined by the minimal total electronic energy. The results of formation enthalpy indicate that Ni and Sc co-doped MgH<sub>2</sub> system is more stable than Ni single-doped system. The hydrogen desorption enthalpies of these two hydrides are investigated. Ni and Sc co-doping can improve the dehydrogenation properties of MgH<sub>2</sub>. The lowest hydrogen desorption enthalpy of 0.30 eV appears in co-doped system, which is significantly lower than that of Ni doping. The electronic structure analysis illustrates that the hybridization of dopants with Mg and H atom together weakens the Mg-H interaction. And the Mg-H bonds are more susceptible to dissociate by Ni and Sc co-doping because of the reduced magnitude of Mg-H hybridization peaks. These behaviors effectively improve the dehydrogenation properties of Ni and Sc co-doped cases.
作者
Gaili Sun
Yuanyuan Li
Xinxin Zhao
Yiming Mi
Lili Wang
Gaili Sun;Yuanyuan Li;Xinxin Zhao;Yiming Mi;Lili Wang(College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai, China;College of Fundamental Studies, Shanghai University of Engineering Science, Shanghai, China)
