H2 dissociative adsorption on Pt3Ti (111)-a density functional theory investigation

The catalytic property of the intermetallic compound Pt3Ti is investigated by studying the interaction of its (111) surface with hydrogen. The study is aimed to provide atomic scale understanding on the behavior of the compound towards hydrogen where previous experimental works showed conflicting observations. Result of this work will have implication to applications such as hydrogenation reactions where hydrogen molecules need to be split in order for the succeeding reaction to occur. Computational technique based on density functional theory is used to obtain the two-dimensional potential energy surface (2-D PES) which describes the energy variation of the system with H-H bond length, r, and distance from the substrate, z, i.e. U = U(r, z). The barrier to H2 dissociation and the binding energy of H atom at the different sites of the substrate are estimated, and the results are compared to that for pure Pt. Charge density distribution is used to explain how Ti atoms modify the surface of the compound relative to the surface of pure Pt. ii

Density functional study on the interaction of hydrogen with Pt 3Ti(111)

We investigate the catalytic property of the intermetallic compound Pt 3Ti by studying the interaction of its (111) surface with hydrogen. Based on density functional theory, we obtain the 2-D PES to estimate the barrier for H2 dissociation, and the binding energy of H atom at different sites of the substrate. The observed energetics can be explained in terms of the role played by the Ti atoms in the compound. Our results show that the Ti atoms function as inactive components that dilute the concentration of the active Pt components thus making the compound less active than Pt towards hydrogen

First principles study of electric and magnetic properties of benzene-iron multiple-decked sandwich chain

We investigate electric and magnetic properties of a benzene-iron multiple-decked sandwich chain [Fe(C6H6)] ∞. By performing first principles calculation based on the density functional theory, we find that the system [Fe(C6H 6)]∞ is stable and has no magnetic moment for which the two succeeding iron atoms are antiferromagnetically arranged. We propose a superexchange interaction mechanism for this antiferromagnetic order. ©2006 The Physical Society of Japan

Pathways for SO2 dissociation on Cu(100): Density functional theory

The dissociation of SO2 on Cu(100) and the diffusion of the co-adsorbed decomposition products S and O were investigated using density functional theory-based calculations. Two dissociation pathways were considered: (P1) and (P2) , the difference being in the formation of the intermediate product SO. It is found that P1 is favored kinetically with a total effective dissociation barrier of 0.78eV compared to P2 which has 1.58eV. The transition state leading to the formation of O+SO is found to be a result of the weakened interaction between the O of SO and the surface while the transition state for breaking SO is seen to be that of the repulsive nature of co-adsorbed S and O. The co-adsorbed S has a lower diffusion barrier of 0.41eV compared to O which has a barrier ranging from 0.49 to 0.95eV. © IOP Publishing Ltd