Hai-Xia Cheng

The stability and catalytic activity of W13@Pt42 core-shell structure

This paper reports a study of the electronic properties, structural stability and catalytic activity of the W13@Pt42 core-shell structure using the First-principles calculations. The degree of corrosion of W13@Pt42 core-shell structure is simulated in acid solutions and through molecular absorption. The absorption energy of OH for this structure is lower than that for Pt55, which inhibits the poison effect of O containing intermediate. Furthermore we present the optimal path of oxygen reduction reaction catalyzed by W13@Pt42. Corresponding to the process of O molecular decomposition, the rate-limiting step of oxygen reduction reaction catalyzed by W13@Pt42 is 0.386 eV, which is lower than that for Pt55 of 0.5 eV. In addition by alloying with W, the core-shell structure reduces the consumption of Pt and enhances the catalytic efficiency, so W13@Pt42 has a promising perspective of industrial application.

The Electronic, Magnetic, and Vibrational Properties of Ce3Co29Ge4B10

We have studied the electronic and vibrational properties of Ce3Co29Ge4B10 compounds using the first-principles GGA + U method. The calculation finds that the magnetic moment of Ce and Co atoms has a good agreement with experimental value when U = 3.8 eV. Also, the calculated lattice constants and atomic positions are corresponding to the experimental results. By using the interatomic pair potential obtained with the lattice inversion method, the phonon density of states of Ce3Co29Ge4B10 compounds is also studied.

Theoretical investigation of geometries, stabilities, electronic and optical properties for advanced Agn@(ZnO)42 (n=6-18) hetero-nanostructure

The structural properties of Agn@(ZnO)42 (n=6-18) core-shell nanoparticles have been investigated by the first principles calculations, and the core-shell nanostructure with n=13 is proved to be the most stable one for the first time. Ag13@(ZnO)42 core-shell nanostructure possesses higher chemistry activity and shows a red shift phenomenon in the light of the absorption spectrum compare to the (ZnO)48, this can be confirmed by the calculated electron structure. The visible-light could be absorbed by Ag13@(ZnO)42 to improve the photo-catalysis of (ZnO)48 nanostructure. Our results show good agreement with experiments.

Atomistic study on the site preference and lattice vibration of Gd{sub 3−x}Y{sub x}Co{sub 29}T{sub 4}B{sub 10} (T=Al and Ge)

Abstract The effects of the Y substitution for Gd on the structural stability and the site preference of intermetallics Gd3−xYxCo29T4B10 (T=Al and Ge) are studied by using a series of interatomic pair potentials. The calculated results show Y can stabilize Gd3−xYxCo29T4B10 with the tetragonal structure, and Y substitute for Gd with a strong preference for the 2b sites. The calculated lattice parameters are in good agreement with the experimental data. Furthermore, the total and partial phonon densities of states are evaluated for the Gd3−xYxCo29T4B10 compounds with the tetragonal structure. A qualitative analysis is carried out with the relevant potentials for the vibrational modes, which makes it possible to predict some properties related to lattice vibration.

The phase stability, magnetic and vibrational properties of A2Ni21B6 (A=Th, U) and Ce3Pd20Si6

By using the interatomic pair potential obtained with the lattice inversion method, the structural properties of A2Ni21B6(A=Th,U) and Ce3Pd20Si6 compounds with Cr23C6 prototype structure are studied. The phase stability of A2Ni21B6 and Ce3Pd20Si6 is tested by high temperature disturbance under the control of the inverted potentials. The calculated lattice parameters are corresponding to the experimental results. We have calculated the magnetic properties and electronic density of states of Ce3Pd20Si6 compounds. Furthermore, the phonon density of states of A2Ni21B6 and Ce3Pd20Si6, the according specific heat and vibrational entropy are calculated first, and a qualitative analysis with pair potentials is also carried out.

Site preferences and lattice vibrations of Nd6Fe13 − x TxSi (T = Co, Ni)*

The site preferences of the rare earth intermetallics Nd6Fe13−xTxSi (T = Co, Ni) are investigated by using interatomic pair potentials which are converted from a lattice-inversion method. Calculation shows that the order of the site preference of Co is 4d, 16k, 16l1, and 16l2 and that of Ni is 16l2, 16l1, 16k, and 4d in Nd6Fe13−xTxSi. Calculated lattice and positional parameters are found to agree with those reported in the literature. Furthermore, the phonon density of states for Nd6Fe13−xTxSi is also evaluated, and a qualitative analysis featuring the coordination and the relevant potentials is carried out.