Lijun Pan

The formation of H2S on metal-modified graphene under hydrogen environments

Abstract The adsorption behaviors of H2S, SH, and S on Co-embedded graphene surface (Co-graphene) are investigated using the first-principles calculations. It is found that the adsorbed SH and S species on Co-graphene are strongly stabilized than that of the H2S molecule. Besides, the chemisorbed SH and S can lead to dramatic changes in the electronic structure and magnetic property of Co-graphene system by the transferred electrons, and the electronic transport behavior of Co-graphene exhibits high sensitivity for detecting SH and S. Moreover, the deposited S-based species would be converted into H2S molecule by the hydrogenation reaction. Compared to the hydrogen molecule, the presence of hydrogen atoms can more easily inhibit the formation of sulfur deposition on Co-graphene surface, which provides valuable guidance on designing graphene-based catalysis as electrode in fuel cells.

Correlations between the Oxygen Ionic Conductivity of Sr- and Mg-doped LaGaO3 and Its Crystal Structure

Oxygen vacancy formation and migration in La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) with various crystal symmetries (cubic, orthorhombic and monoclinic) are studied by employing first-principles calculations based on density functional theory (DFT). The calculated vacancy formation energy of the cubic LSGM is 3.96 eV, much lower than those of orthorhombic and monoclinic LSGM. The calculated averaged migration energies increase in the order of

Structural and electronic distortions in hydrogenated single-walled zigzag carbon nanotubes

In this paper, we have investigated hydrogenated single-wall zigzag carbon nanotubes from (7,0) to (11,0) by using pseudopotential-based density functional theory. We found that the structure deformation of configuration follows the way preserving high symmetry as possible. One typical process that two dimer chains along the axis direction separate on CNT is presented. The configuration is more stable as the inter-dimer distance increases. Meanwhile, the carbon bond angles decrease differently due to the hydrogen adsorption site or not, but the C-C band length is insensitive to the dimer chains separation process. The electronic distortions are demonstrated that all configurations show metal behavior for zero interval and the gaps undergo increment with the dimer chains separation increment regardless of tubes chirality, which is related to the hybridization resulting in changing the free electron state and the Fermi level. Furthermore, there is a localized electron distribution behavior difference at hydrogenated carbon site or not.