کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1276533 | 1497507 | 2014 | 7 صفحه PDF | دانلود رایگان |
• The predominated defect in MgH2 are charged H vacancy.
• F and Cl impurities tend to substitute for H atom with the neutral state.
• F and Cl can decrease the removal energy for positively charged H atom in MgH2.
Using first-principles calculations, we investigated the structural properties and formation energies of H-related intrinsic defects and F- or Cl-related impurities in MgH2. It was found that hydrogen vacancy and interstitial are favorable in charged states, whereas F and Cl impurities tend to substitute for hydrogen atom with the neutral state. We showed that F and Cl cannot lead to decrease of the removal energy for neutral and negatively charged H atom, but both of them can markedly decrease the removal energy for positively charged H atom. This result provides an explanation for the experimentally observed lowering of the onset temperature for hydrogen desorption from TiF3- and TiCl3- doped MgH2.
Journal: International Journal of Hydrogen Energy - Volume 39, Issue 2, 13 January 2014, Pages 877–883