Abstract
The adsorption of H2 on LaNiO3 was investigated using density functional theory (DFT) calculations. The adsorption sites, adsorption energy, and electronic structure of LaNiO3(001)/H2 systems were calculated and indicated through the calculated surface energy that the (001) surface was the most stable surface. By looking at optimized structure, adsorption energy and dissociation energy, we found that there were three types of adsorption on the surface. First, H2 molecules completely dissociate and then tend to bind with the O atoms, forming two –OH bonds. Second, H2 molecules partially dissociate with the H atoms bonding to the same O atom to form one H2O molecule. These two types are chemical adsorption modes; however, the physical adsorption of H2 molecules can also occur. When analyzing the electron structure of the H2O molecule formed by the partial dissociation of the H2 molecule and the surface O atom, we found that the interaction between H2O and the (001) surface was weaker, thus, H2O was easier to separate from the surface to create an O vacancy. On the (001) surface, a supercell was constructed to accurately study the most stable adsorption site. The results from analyses of the charge population; electron localization function; and density of the states indicated that the dissociated H and O atoms form a typical covalent bond and that the interaction between the H2 molecule and surface is mainly due to the overlap-hybridization among the H 1s, O 2s, and O 2p states. Therefore, the conductivity of LaNiO3(001)/H2 is stronger after adsorption and furthermore, the conductivity of the LaNiO3 surface is better than that of the LaFeO3 surface.
Highlights
ABO3 perovskites are a group of inexpensive materials that possess high capacities; fast charge and discharge capabilities; and universally present the phenomenon of hydrogen storage
Wærnhus et al [4] reported on the electrical conductivity of polycrystalline LaFeO3 as a function of the thermal properties of the materials; and that the conductivity of LaFeO3 was affected by annealing for extended periods at temperatures above 1000 ◦ C, prior to the conductivity measurements
The 3 × 3 supercell was adopted (Figure 3i); the H2 molecule was located on the T1, T2 and
Summary
Changchang Pan 1,2 , Yuhong Chen 1,2, *, Na Wu 1,2 , Meiling Zhang 2,3 , Lihua Yuan 2 and Cairong Zhang 1,2. The School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China. Received: 28 October 2016; Accepted: 31 December 2016; Published: 5 January 2017
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