Fazhi Xie

Characterization of Pd/TiO2 embedded in multi-walled carbon nanotube catalyst with a high photocatalytic activity

Pd particles loading on TiO2-embedded multi-walled carbon nanotubes (MWCNTs), MWCNTs, and TiO2 particles were prepared via an impregnation method with palladium(II) chlorate solution followed by heat treatment at high temperature. To characterize the catalysts, BET surface area, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive X-ray, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy were employed. The prepared catalysts were tested in degradation of methyl orange under visible light. Pd/TiO2-MWCNTs catalyst demonstrates the highest photocatalytic activity, and the phase transformation from PdO to Pd0 phase takes place at heat treatment of embedded TiO2. The nanoparticles size of TiO2 can be decreased by introduction of MWCNTs species. Combining structural characterization with kinetic study results we could conclude that the superior catalytic performance could arise due to the Pd/TiO2-MWCNTs catalyst’s structure.

A series of novel cadmium(II) coordination polymers with photoluminescence and ferroelectric properties based on zwitterionic ligands

A series of Cd(II) compounds, abbreviated as {[Cd·L·(BTC)0.5·H2O]·(H2O)3}n (1), [Cd5·(PO4)2·(HPO4)2·(H2O)4]n (2) and {[Cd2.5·L·(BTC)1.5·(H2O)1.5·(DMF)]·(H2O)2.35}n (3), were obtained by using a zwitterionic ligand (1,1′,1′′-(2,4,6-trimethybenzene-1,3,5-triyl)-tris(methylene)tris(4-carboxypyridinium) tribromide, H3LBr3) and an aromatic secondary ligand (H4BTC). Structure determination confirmed that compounds 1 and 3 possess the structure of 1D and 2D metal–organic frameworks respectively while compound 2 belongs to a novel inorganic crystal, which may be produced by introducing different categories and concentrations of inorganic acids. In addition to reasonable thermal stability (up to 300 °C), the titled Cd(II) compounds exhibited different photoluminescence emissions in the solid state resulting from coordination environments and crystal structures. Moreover, compound 3 also exhibited a ferroelectric behavior with a saturated spontaneous polarization (Ps) of 0.20 μC cm−2, indicating that compound 3 is a potential ferroelectric material at room temperature.

Electrochemical detection of Cu(II) using amino-functionalized MgFe2O4/Reduced graphene oxide composite

In this study, an amino-functionalized MgFe2O4/reduced graphene oxide (rGO) composite was prepared by the combination of MgFe2O4/rGO and 1,6-hexanediamine (HDA) and employed for the electrochemical detection of Cu(II) ions. The composite was obtained through a one-pot method, and it was characterized by SEM, XRD, FT-IR and electrochemical methods. Some important parameters such as pH of solution, amount of modification, deposition time, and deposition potential were optimized. The determination of Cu(II) ions was performed using HDA/rGO/MgFe2O4, rGO/MgFe2O4 and MgFe2O4via square-wave anodic stripping voltammetry. The lowest detection limit obtained was 0.2 nM, and the sensitivity was 0.0172 μA nM−1. The proposed electrode was also used for the detection of Cu(II) ions in soil sample. Overall, the proposed method could provide a reference for the detection of metal ions.

Graphene/BiOI composites synthesized via the oil bath method and their application for efficient photocatalytic degradation of methyl orange under visible light irradiation

An efficient and simple oil bath method for rapid synthesis of graphene/BiOI as visible light active photocatalyst was described. The resultant graphene/BiOI composites were characterized by different techniques, including scanning electron microscopy, X-ray diffraction, and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic activity of the as-prepared graphene/BiOI composites for methyl orange degradation was also investigated under visible light irradiation. The results show that BiOI and graphene taken with a mass ratio of 100: 1 exhibited the highest photocatalytic efficiency, which is two times that of pure BiOI. Part of this effect results from higher specific surface area that provides an increased number of active sites. A relatively narrow band gap (2.08 eV) formed in the heterostructure can also contribute to this effect. A suggestion of the photocatalytic mechanism was also offered.