Yanxing Qi

Investigation of a Branchlike MoO3/Polypyrrole Hybrid with Enhanced Electrochemical Performance Used as an Electrode in Supercapacitors

A branchlike MoO3/polypyrrole conductive nanocomposite was facilely prepared by wrapping a homogeneous polypyrrole (PPy) layer around MoO3 nanobelts via the in situ oxidative polymerization of a self-assembled pyrrole monomer. X-ray powder diffraction characterization demonstrated that the PPy polymer does not hinder the crystallization of the MoO3 nanobelts substrate. The electrochemical tests show that the specific capacitance of 129 F g(-1) for the MoO3/PPy hybrid is higher than both pristine MoO3 and pure PPy. Moreover, the hybrid electrode with good electrical conductivity displays good cyclic stability of 90% retention after 200 cycles of charge/discharge. These results indicate a promising potential application of the MoO3/PPy nanocomposite for use as an effective electrode material in supercapacitors.

Mesoporous silica-supported copper-catalysts for homocoupling reaction of terminal alkynes at room-temperature

Amine-functionalized mesoporous silica-supported copper catalysts SBA-15@amine–Cu and SBA-15@Oamine–Cu were prepared and proved to be efficient and reusable for homocoupling of terminal alkynes at room temperature with air as the oxidant. SBA-15@amine–Cu exhibited better recyclability than SBA-15@Oamine–Cu. The differences in the catalytic performances of the catalysts could be ascribed to catalyst structure and the interaction between copper and the supports. The as-prepared catalysts were systematically characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), high resolution-transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and nitrogen physical adsorption. The analysis indicated that the mesoporous structure of the materials was retained during the immobilization process. XPS results suggested that the as-prepared catalysts were not obtained by a simple physical adsorption of CuCl on the supports. It is noted that, for aliphatic alkynes, the catalytic activity of SBA-15@amine–Cu is even higher than that of the homogeneous copper catalytic system and that of some previously reported heterogeneous systems.

Efficient Charge Separation between Bi and Bi2MoO6 for Photoelectrochemical Properties

Herein, porous Bi/Bi2 MoO6 nanoparticles have been prepared by a facile in-situ reduction approach. Moreover, the morphology and Bi content of product could be controlled by varying the reaction time. By controlled fabrication, the desired porous Bi2 MoO6 nanostructure with incorporation of Bi was obtained and exhibited high photoelectric and photocatalytic activity. In particular, the samples yield a photocurrent density of 320 μA cm(-2) , which is 3.2 times that of the pure Bi2 MoO6 nanosheet (100 μA cm(-2) ) under the same conditions. UV/Vis diffuse reflectance spectroscopy analysis confirmed the surface plasmon resonance in the as-prepared porous nanoparticles. The improved photoelectric properties could be the synergistic effect of the porous structure with large surface area and effective electron-hole separations between Bi and Bi2 MoO6 .

One-pot synthesis of 3D flower-like heterostructured SnS2/MoS2 for enhanced supercapacitor behavior

Novel three-dimensional flower-like heterostructured SnS2/MoS2 was produced via a one-step hydrothermal method. The full potential of the heterostructured SnS2/MoS2 material could be realized because of a strong synergetic effect, which was not only able to effectively weaken the agglomeration and restacking problems during the electrochemical reaction, but also able to ensure the high-rate and long-life. We found that SnS2/MoS2 had better electrochemical performance compared to MoS2, due to the rapid electronic transport and volume change buffering of the formation of the SnS2/MoS2 heterostructure. The electrochemical tests showed that the SnS2/MoS2 electrode had a specific capacitance of 105.7 F g−1 at a current density of 2.35 A g−1 and it displayed good cyclic stability of 90.4% retention even after 1000 cycles, which indicated that the SnS2/MoS2 was an useful potential electrode material for the application of energy storage and deserves to be further investigated.

Selective adsorption of silver ions from aqueous solution using polystyrene-supported trimercaptotriazine resin

Trimercaptotriazine-functionalized polystyrene chelating resin was prepared and employed for the adsorption of Ag(I) from aqueous solution. The adsorbent was characterized according to the following techniques: Fourier transform infrared spectroscopy, elemental analysis, scanning electron microscopy and the Brunauer-Emmet-Teller method. The effects of initial Ag(I) concentration, contact time, solution pH and coexisting ions on the adsorption capacity of Ag(I) were systematically investigated. The maximum adsorption capacity of Ag(I) was up to 187.1 mg/g resin at pH 0.0 and room temperature. The kinetic experiments indicated that the adsorption rate of Ag(I) onto the chelating resin was quite fast in the first 60 min and reached adsorption equilibrium after 360 min. The adsorption process can be well described by the pseudo second-order kinetic model and the equilibrium adsorption isotherm was closely fitted by the Langmuir model. Moreover, the chelating resin could selectively adsorb more Ag(I) ions than other heavy metal ions including: Cu(I), Zn(II), Ni(II), Pb(II) and Cr(III) during competitive adsorption in the binary metal species systems, which indicated that it was a highly selective adsorbent of Ag(I) from aqueous solution.

Facile growth of Bi2MoO6 nanosheet arrays on Ni foam as an electrode for electrochemical applications

A facile hydrothermal reaction has been developed for the large-scale growth of Bi2MoO6 nanosheets on conductive substrates with robust adhesion as high performance electrodes for electrochemical capacitors. It was found that the nickel foam facilitates the formation of a uniform nanosheet array with fast electron and ion transportation, a large electroactive surface area and an excellent structural stability. As a result, it shows a specific capacitance of 37.3 F g−1 even at a current density of 2 A g−1 and a high cycling stability with 89% retention of its initial specific capacitance after 1000 cycles in 1 M KCl solution. These results provide a way of fabricating Bi2MoO6 nanosheet arrays as efficient electrodes for electrochemical capacitors.

Facile synthesis of three-dimensional flower-like MoO2–graphene nanostructures with enhanced electrochemical performance

Novel three dimensional MoO2–graphene (MoO2–G) flower-like nanostructures are synthesized via a facile hydrothermal reaction. It has been shown that the MoO2–G demonstrates enhanced supercapacitive performance compared to pure MoO2 particles. The excellent electrochemical performance is attributed to the introduction of graphene and a hierarchical nanostructure, providing a large surface area and low equivalent series resistance.

Partial Oxidation of Alcohols to Aldehydes and Ketones Under Mild Conditions

Abstract A number of aldehydes and ketones were prepared by partial oxidation of alcohols in air catalyzed by RuO2/ZSM‐5 which can be easily prepared with the industrial grade ZSM‐5 and RuCl3 · xH2O.

Synthesis of Guanidine Derivatives and Molecular Recognition

Abstract Five Guanidine Derivatives bearing acyl group were synthesized by the reaction of acyl chloride with 1,1,3,3-tetramethylguanidine. Their structures were confirmed by IR, 1H-NMR, EI-MS, HRMS and elementary analysis. One of them (4a) was also characterized by X-ray. Preliminary results of interaction with phosphate-containing biomolecules and adipate showed that all of them exhibited the abilities of molecular recognition.

Feature Designed Growth of 3D Flower-like SiO2 Growing on Polyethyleneimine Modified CaCO3 Microparticles

We report on the ability to create complex 3D flower-like SiO2 in vitro via CaCO3 microparicles supported by polyethyleneimine mediated biosilicification under experimentally altered chemical influences. The morphology, structure, composition of the product have been investigated with the X-ray photoelectron spectrum, scanning electron microscope, transmission electron microscope, and energy-dispersive spectroscopy. The overall morphologies could be controlled to shift from a characteristic network of flower-like silica sphere to a sheet-like structure by adjusting physical adsorption of different amount of polyethyleneimine onto the surface of the CaCO3 microparticles.