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Zhu J.,Fuzhou University | Jin H.,Fuzhou University | Zang L.,Fuzhou University | Li Y.,Fuzhou University | And 7 more authors.
Journal of Physical Chemistry C | Year: 2011

A series of nonstoichiometric tritungsten oxide clusters W 3On (n = 7, 8, 10) deposited on the TiO2(110) surface have been investigated by using first-principles DFT calculations. Various possible configurations have been considered for each W 3On/TiO2(110) system, based upon ab initio molecular dynamics simulations and thermodynamical analyses. After deposition of the W3On cluster, the position of the Fermi level is sensitive to the stoichiometry of the cluster. This is due to the obvious charge transfer occurring from the oxygen-deficient W3On cluster (n < 9) to the TiO2(110) surface, whereas the direction of charge transfer is reversed for the deposition of the oxygen-enriched W 3On cluster (n > 9). Our results clearly indicate that the deposition of clusters with different stoichiometric compositions offers an opportunity to control the properties of the support, including the conductivity, the surface work function, and the catalytic performance over a sufficient range. In addition, our results show that the relative stability of nonstoichiometric tritungsten oxide clusters in the gas phase is not preserved after landing on the TiO2(110) surface. Therefore, from a thermodynamical point of view, it may provide a possible way to stabilize the unstable clusters in the gas phase by choosing a suitable support. © 2011 American Chemical Society. Source


Chen F.,Ningde Normal University | Yan G.,Ningde Normal University | Yan G.,Research Institute of Photocatalysis | Zheng L.,Fujian Normal University | And 5 more authors.
Journal of Materials and Environmental Science | Year: 2015

Silver, carbon-doped TiO2 absorbent was obtained using hydrothermal method with titanium sulfate as a titanium source. Reactive brilliant red X-3B was used as a target degradation material to evaluate its adsorption activity. Physicochemical properties of the absorbent was characterized by analytical techniques such as XRD, SEM-EDS, TG-DTG, TEM-HRTEM, BET, and XPS. The results showed that the synthesized samples has a phase of anatase with typical mesoporous structure, and it also has a good adsorption activity of reactive brilliant red X-3B. The Ag-C-TiO2 (calcined at 500°C) absorbent's discoloration rate for reactive brilliant red X-3B (50 ppm) reached 97% after adsorption for 60minutes at absorbent of 1.5 g/L(50 ppm reactive brilliant red X-3B solution), and solution pH of 7~9. This type of Ag-C co-doped TiO2 could potentially be used as absorbent for dye wastewater treatment based on its unique physicochemical properties. Source


Huang X.-H.,Fuzhou University | Huang X.-H.,Research Institute of Photocatalysis | Huang X.-H.,CAS Fujian Institute of Research on the Structure of Matter | Xiao Z.-P.,Fuzhou University | And 4 more authors.
Journal of Coordination Chemistry | Year: 2015

(Figure Presented). Two silver(I) compounds, [Ag(H2mbpz)(Hchda)]n (1) and [Ag2(H2mbpz)2(oba)]n (2) (where H2mbpz = 3,3′,5,5′-tetramethyl-4,4′-bipyrazole, H2chda = trans-cyclohexane-dicarboxylic acid and H2oba = 4,4′-oxy-bis-benzoic acid), have been synthesized and characterized by single-crystal X-ray diffraction analyses. In both cases, the Ag(I) centers are linked by H2mbpz ligands to form 1-D Ag(I)-H2mbpz chains; then, the Ag(I)-H2mbpz chains connect with two neighboring congeners through Ag⋯Ag interactions, forming 2-D supramolecular layers. In 1, the dicarboxylate is monodeprotonated and linked to form an anion chain through strong hydrogen bonding interaction. Such anion chains attach on two sides of the supramolecular layers via Ag-O bonds to form a neutral sandwich-like layered network. In 2, the dicarboxylate is fully deprotonated and adopts a μ2-η1:η1 mode to link two adjacent supramolecular layers to form a twofold interpenetrating 3-D supramolecular network. The thermal stability and luminescence of 1 were also studied. © 2015 Taylor & Francis. Source


Ding K.-N.,Fuzhou University | Ding K.-N.,Research Institute of Photocatalysis | Li Y.-L.,Fuzhou University | Zhang Y.-F.,Fuzhou University
Jiegou Huaxue | Year: 2014

The electronic structures and optical properties of II-III 2-VI4 (II = Zn, Cd; III = In; VI = Se, Te) compounds are studied by the density functional theory (DFT) using the Vienna ab initio simulation package (VASP). Geometrical optimization of the unit cell is in good agreement with the experimental data. Our calculations show that the valence band maximum (VBM) and conduction band minimum (CBM) are located at G resulting in a direct energy gap. The optical properties are analyzed, and the independent second harmonic generation (SHG) coefficients are determined. By an analysis of the band structure, we can get that SHG response of the system can be attributed to the transitions from the bands near the top of valence band that are derived from the Se/Te p states to the unoccupied bands contributed by the p states of In atoms. Source


Jin H.,Fuzhou University | Zhu J.,Fuzhou University | Hu J.,Fuzhou Command Academy | Li Y.,Fuzhou University | And 6 more authors.
Theoretical Chemistry Accounts | Year: 2011

Geometries and electronic structures of WO3(001) surface and a series of stoichiometric (WO3)n clusters (n = 1-6) have been systematically investigated using first-principles density functional calculations. Six possible reconstructured models of WO3(001) surface with cubic phase are explored, and the most stable configuration is the (√2×√2)R45° surface. The main feature of WO3(001) surface is that the top of valence band is dominated by the 2p states of the bridging oxygen atom, rather than the top terminal oxygen. By comparing the geometrical parameters, from the structural point of view, the W3O9 cluster can be used as the smallest molecular prototype of the WO3 surface. However, in terms of the electronic structure, only until W6O18, the cluster begins to appear the electronic feature of the WO3(001) surface. This may be due to the reason that the W6O18 cluster and the top layer of WO3(001) surface show similar "stoichiometry" if we treat two kinds of oxygen atoms as different "elements". In addition, for the chemical reactivity, using BH3 as a probe molecule, the W6O18 cluster also bears general resemblance to the WO3(001) surface, and the bridging oxygen atoms in two systems are the preferred sites for the nucleophilic reaction. Therefore, our results indicate that the W6O18 cluster with a spherical buckyball structure can be viewed as the smallest molecular model to understand the properties such as catalytic activity of WO3(001) surface. © 2011 Springer-Verlag. Source

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