Xiao-Xu Wang

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 structural, magnetic and optical properties of TM n @(ZnO) 42 (TM = Fe, Co and Ni) hetero-nanostructure

The magnetic transition-metal (TM) @ oxide nanoparticles have been of great interest due to their wide range of applications, from medical sensors in magnetic resonance imaging to photo-catalysis. Although several studies on small clusters of TM@oxide have been reported, the understanding of the physical electronic properties of TMn@(ZnO)42 is far from sufficient. In this work, the electronic, magnetic and optical properties of TMn@(ZnO)42 (TM = Fe, Co and Ni) hetero-nanostructure are investigated using the density functional theory (DFT). It has been found that the core-shell nanostructure Fe13@(ZnO)42, Co15@(ZnO)42 and Ni15@(ZnO)42 are the most stable structures. Moreover, it is also predicted that the variation of the magnetic moment and magnetism of Fe, Co and Ni in TMn@ZnO42 hetero-nanostructure mainly stems from effective hybridization between core TM-3d orbitals and shell O-2p orbitals, and a magnetic moment inversion for Fe15@(ZnO)42 is investigated. Finally, optical properties studied by calculations show a red shift phenomenon in the absorption spectrum compared with the case of (ZnO)48.

First-principles investigation on Au n @(ZnO)42 (n = 6–16) core-shell nanoparticles: structure stability and catalytic activity

A family of Au n @(ZnO)[Formula: see text] ([Formula: see text]-16) cluster-assembled nanoparticles are studied by density-functional theory calculations. Different sizes, up to 100 atoms, are considered for several compositions. For each n, we design and construct a converged model for Au n @(ZnO)[Formula: see text] to analyze the coupling effect of adding Au atoms into ZnO outer shell. Among the optimized geometrical structures, we find that [Formula: see text]@(ZnO)[Formula: see text] has the most stable structure. The electronic properties, optical properties and catalytic activity of the [Formula: see text]@(ZnO)[Formula: see text] core-shell have been systematically investigated, which also shows consistency with the experimental results. It is found that forming a core-shell structure enhances the visible-light photocatalytic ability and [Formula: see text]@(ZnO)[Formula: see text] core-shell structure has a high catalytic efficiency for the reaction CO oxidation.

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.