Chen P.,Shaanxi University of Science and Technology
Journal of Sol-Gel Science and Technology | Year: 2017
Abstract: Interface-induced effect of nanocomposites are attracting many attentions because the potential advantages in environment decontamination. This work present the synthesis and enhanced photocatalytic activities of novel reduced graphene oxide-ZnFe2O4 nanocomposites. The nanocomposites showed obviously greater sunlight-excited photocatalytic and Fenton-like photocatalytic activities than the nanoparticles. The photocatalytic activities enhanced with increasing rGO/ZnFe2O4 ratio and related with initial pH and H2O2 content. The good photocatalytic activities are ascribed to the interface charge transfer that is confirmed by optical conducitivity. Moreover, the nanoparticles and nanocomposites was ferromagnetic, thereby being magnetically separable. The nanocomposites also showed good adsorption ability to the dye, and so the remained dye and intermediates can be magnetically removed together with the reusable nanocomposites. Graphical abstract: [InlineMediaObject not available: see fulltext.] © 2017 Springer Science+Business Media New York
He H.-Y.,Shaanxi University of Science and Technology
Nano | Year: 2017
Reduced graphene oxide-SnSe (rGO-SnSe) nanohybrids were synthesized with a solution chemical reaction at room temperature. The nanohybrids were characterized by various techniques for their microstructural and photocatalytic activities in photodegradation of alkaline dye malachite green in the water. The effects of rGO/SnSe ratio, initial solution pH, and H2O2 concentration on the photodegradation efficiency were studied. The SnSe nanocrystallines with nanoscale size and narrow bandgap were formed and uniformly adhered on the rGO surface. Raman analysis confirmed the reduction of GO. The experimental results indicated that the nanohybrids showed excellent sunlight-excited photocatalytic activity in degrading malachite green in the water. Significantly, the nanohybrids showed remarkable photo-Fenton-like catalytic activity. The photodegradation rates of the hybrids were greater than that of SnSe nanoparticles, increased with increasing rGO/SnSe ratio, and related to operation parameters. High photocatalytic activities were ascribed to the efficiency interface effect that was confirmed by the calculations of band energy level and photoconductivity. The TOC measurement further verified the photodegradation results. The nanoparticles and nanohybrids also showed excellent reusability. © 2017 World Scientific Publishing Company
He J.,Shaanxi University of Science and Technology |
Hou Z.,Shaanxi University of Science and Technology
Advances in Engineering Software | Year: 2012
In order to separate the conflict of the traffic flow effectively, time delay, number of stops and traffic capacity are chosen as performance indexes, and the objective function related to the cycle time and the saturation of an intersection is established by using the weighting coefficients. Then, based on the uncertainty and convergence analysis of ant colony algorithm (ACA), computational experiments are conducted and numerical comparisons are made for the values of performance indexes achieved by the signal timing optimization problem with Webster algorithm, genetic algorithm (GA) and ACA. Numerical results show that ACA is a simple and feasible method for signal timing optimization problems. © 2011 Elsevier Ltd. All rights reserved.
Xue C.-H.,Shaanxi University of Science and Technology |
Ma J.-Z.,Shaanxi University of Science and Technology
Journal of Materials Chemistry A | Year: 2013
Prolonging the lifetime of superhydrophobic surfaces is required so that the materials can be used practically. Thus, great efforts have been made in designing surfaces that maintain micro- and nanoscaled hierarchical structures and low surface-energy property, which are necessary for superhydrophobicity, during use. It was demonstrated that improving surface mechanical strength to increase wear resistance helps maintain hierarchical roughness, retarding the loss of superhydrophobicity. Additionally, designing self-healing materials that can recover their structure and/or properties when damaged has been suggested and demonstrated to sustain the superhydrophobicity of surfaces. This review focuses on recent advances in developing mechanically durable, corrosion-resistant, self-healing, and easily repairable superhydrophobic surfaces, which will enable prolonged lifetime of superhydrophobicity for practical applications in the future. © The Royal Society of Chemistry 2013.
He H.Y.,Shaanxi University of Science and Technology
Materials Research Innovations | Year: 2010
Nano-N doped TiO2 powders were synthesised with solvothermal processes. Four kinds of starting compositions were used for solvothermal syntheses of N doped TiO2 powders. The powders were characterised with XRD, SEM and spectrophotometry. The powder synthesised with titanium sulphate and diethylenetriamine has the highest N content of 17.4 mol.-%. The N content in the powder depends on the starting composition, in which the mechanism is discussed. N doping narrows the band gap of the powder and introduces indirect band gap to the powders, which respectively extend the absorption edge to visible light region and longer wavelength. The experiment of photodegradation on the synthesised powders indicated that the degradation rate of methyl orange increased with the light adsorption edge of the powder and the N content in the powder. © W. S. Maney & Son Ltd. 2010.
He H.-Y.,Shaanxi University of Science and Technology
Materials Science in Semiconductor Processing | Year: 2015
A series of ZnO-reduced graphene oxide (ZnO-rGO) nanocomposite films were developed on glass substrate by a sol-gel technique. The deposited films were highly transparent and showed enhanced photocatalytic activity with increasing rGO content. Significantly, the films showed surface hydrophilicity and photoinduced superhydrophilicity that enhanced with the increase of rGO/ZnO ratio. The enhancement of photocatalytic activity of ZnO-rGO films with increasing rGO/ZnO ratio is attributed to the enhancement of their efficient charge separation owing to electrons injection from the conduction band of ZnO to graphene, the decrease of average particle size, and the increase of superhydrophilicity. The promising characteristics (inexpensive, transparent, photoinduced superhydrophilic, and highly photocatalytically active) make the ZnO-rGO films have the potential use in self-cleaning and various indoor applications. © 2014 Elsevier Ltd.
Wang J.,Shaanxi University of Science and Technology |
Zhang D.,Xi'an Technological University
Advances in Polymer Technology | Year: 2013
One-dimensional nanostructured polyaniline (1D nano-PANI), including nanofibers, nanowires, nanobelts, nanotubes, nanorods, nanoneedles, and nanosticks, has been extensively studied recently due to its unique properties and many potential applications. As a continuation of our previous review on 1D nano-PANI (D. H. Zhang and Y. Y. Wang, Mater Sci Eng B 2006, 134(1), 9-19), the research and development of 1D nano-PANI, including both syntheses and applications, in the past 5 years (2006-2010) are reviewed in this paper. Newly invented chemical methods for fabrication of 1D nano-PANI, such as solid-state polymerization, seeding polymerization, UV light- and microwave-assisted polymerization, plasma-induced polymerization, porous membrane controlled polymerization, and vapor phase polymerization, are briefly reviewed, and morphology controlling of the nanostructures during several synthesizing processes are reported and discussed at first. The formation mechanisms and key factors that affect the morphology evolution of the 1D nano-PANI are discussed. Novel features of 1D nano-PANI, such as aligned or oriented, longer, self-doped, chiral, derivative, carbonized, and dendritic PANI, are summarized. Finally, newly exploited applications of 1D nano-PANI in the past few years, such as sensors (e.g., gases sensors, biosensors, moisture or humidity sensors, TNT sensors, taste sensors, and noble metal ion sensors), absorbents, catalysts, actuators, supercapacitors, batteries, fuel cells, solar cells, electrochromic devices, hydrogen storages, surface modifiers, field-effect transistors, and functional materials, are discussed in detail. © 2012 Wiley Periodicals, Inc.
Liu Y.P.,Shaanxi University of Science and Technology
International journal of molecular sciences | Year: 2010
Rapid synthesis of 4-ethyloctanoic acid by means of microwave irradiation is described. Diethyl malonate reacted with 2-ethyl-1-bromohexane in the presence of sodium ethoxide to give diethyl (2-ethylhexyl)malonate (1b). 1b was saponified in the solution of ethanol and potassium hydroxide and then acidified to form (2-ethylhexyl)propanedioic acid (1c), and 1c was heated and decarboxylized to give 4-ethyloctanoic acid (1d). The influence of reaction temperature and reaction time on the yield of 1b and the effect of reaction time on the yield of 1c and 1d were investigated in order to optimize the synthetic conditions. The relative optimal conditions for the synthesis of 1b were a mole ratio of sodium to diethyl malonate to 2-ethylhexyl bromide of 0.1:0.11:0.11, a reaction temperature of 80-85 °C, and a reaction time of 2-2.5 h. The yield of 1b was about 79%. 1b was saponified for 30 min and then acidified to form 1c, and the yield of 1c was 96%. 1c was heated for 16 min at 180°C to give 1d, and the yield of 1d was about 90%. The overall yield of 1d is 70% under microwave irradiation. The reaction time was reduced greatly. In order to compare the result of microwave irradiation with that of an oil bath, the reactions were also performed in an oil bath. The structures of intermediates, product and by-product were confirmed by HRMS, (1)H NMR, (13)C-NMR and IR.
He H.Y.,Shaanxi University of Science and Technology
Journal of Materials Science: Materials in Electronics | Year: 2012
The nickel cobalt ferrite (Co 0.5Zn 0.5Fe 2O 4) nanopowders were synthesized by a sol-gel method and a hydrothermal method. Polyethylene glycol (PEG-4000) and carboxymethyl cellulose (CMC) were used as the templating agents for controlling the anisotropy and the microstructure of the Co0.5Zn0.5Fe2O4 nanopowders. The microstructure and magnetic property of the synthesized powders were comparatively studied. The results indicated that the synthesis technique and the template had remarkable dependence on the microstructure and the magnetic property of the nanopowders. The powder synthesized by the sol-gel method without any template had a maximum saturation magnetization of 73.6 emu g -1 closing to the value of the bulk material (80 emu g -1), while the PEG- 4000 and CMC decreased the magnetization to 54.0 and 60.9 emu g -1. The three powders showed almost same coercivity (314-343 Oe). However, the PEG-4000 and CMC in the hydrothermal process obviously decreased and increased the coercivity respectively from 1,464 Oe to 5 Oe and 4,304 Oe but had small effect of the magnetization (55.5-59.0 emu g -1). © 2011 Springer Science+Business Media, LLC.
Hua L.,Shaanxi University of Science and Technology |
Ma H.,Shaanxi University of Science and Technology |
Zhang L.,Shaanxi University of Science and Technology
Chemosphere | Year: 2013
Three azo dyes (Methyl Orange, Direct Brown and Direct Green) were treated by catalytic wet air oxidation (CWAO) with the catalysts CuO/γ-Al2O3 prepared by consecutive impregnation. The relationship of decolorization extent, chemical oxygen demand (COD) removal extent and total organic carbon (TOC) in dye solution were investigated. The results indicated that the CuO/γ-Al2O3 catalyst had excellent catalytic activity in treating azo dyes. Almost 99% of color and 70% of TOC were removed in 2h. The high removal extent of color and TOC indicated that the CWAO obtained perfect decomposition for pollutants. The degradation pathway of azo dyes was analyzed by UV-Vis, FTIR and MS. According to the examined results, the hydroxyl (OH) radicals induced strong oxidizing effects in the target solution and destroyed the chromophoric groups of azo-benzene conjugated of the molecular structure. Considering characteristics of the dye structure, the azo bond (NN) would first be attacked by the hydroxyl radical and other free radicals. With the continuous oxidization and the long reaction time at high temperature, these intermediates could be oxidized to the final oxidation products, such as water and carbon dioxide. © 2012 Elsevier Ltd.