| 摘要: | The adsorption and dehydrogenation of water on Fe(111), W@Fe(111), and W-2@Fe(111) surfaces have been studied via employing the first-principles calculations method based on the density functional theory. The three adsorption sites of the aforesaid surfaces, such as top (T), 3 fold-shallow (S), and 3-fold-deep (D), were considered. The most favorable structure of all OHx (x = 0-2) species on the surfaces of Fe(111), W@Fe(111), and W-2@Fe(111) have been thoroughly predicted and discussed. Our calculated results revealed that the adsorbed configurations of FeH2O(T-eta(1)-O)-b, W@FeH2O(T-eta(1)-O)-a, and W-2@FeH2O(T-eta(1)-O)-a possess energetically the corresponding adsorption energies of -8.08, -13.37, and -18.61 kcal/mol, respectively. In addition, the calculated activation energies for the first dehydrogenation processes (HO-H bond scission) of H2O on Fe(111), W@Fe(111), and W-2@Fe(111) surfaces are 24.40, 12.62, and 9.97 kcal/mol, respectively. For second dehydrogenation processes (O-H bond scission), the corresponding activation energies of OH on Fe(111), W@Fe(111), and W-2@Fe(111) surfaces are 39.35, 22.69, and 26.24 kcal/mol, respectively. Finally, the entire dehydrogenation courses on the varied Fe(111), W@Fe(111), and W-2@Fe(111) surfaces are exothermic by 20.08, 41.35, and 59.30 kcal/mol, respectively. To comprehend the electronic properties of its nature of interaction between the adsorbate and substrate, we calculated the electron localization functions, local density of states, and Bader charges; the results were consistent and explicable. |
