Ti/SnO2+SbOx/MnO2(Ce)电极制备及性能表征

采用热分解法制备了不同浓度稀土元素铈掺杂钛基二氧化锰电极,通过SEM、极化曲线和EIS测试等方法分析了自制电极的形貌、催化性能和废水处理效果等.结果表明:适量铈元素的掺杂能改善二氧化锰电极的表面形貌,提高电极的析氯电催化活性,增强电极的耐蚀性和稳定性;使其在氯化钠电解质体系中处理亚甲基蓝印染废水的色度去除率达到96.9％,COD去除率达到91.8％.     

Synthesis and characterization of a new monophosphate (5-Cl-2,4-(OCH3)2C6H2NH3)H2PO4

Chemical preparation, crystal structure and NMR spectroscopy of a new organic cation 5-chloro(2,4-dimethoxy)anilinium monophosphate H₂PO₄ are given. This new compound crystallizes in the monoclinic system, with the space group P2₁/c and the following parameters: a = 5.524(2) Å, b = 9.303(2) Å, c = 23.388(2) Å, β = 90.66(4), V = 1201.8(2) Å³, Z = 4 and D_x = 1.573 g cm⁻³. Crystal structure has been determined and refined to R = 0.031 and R_w = 0.080 using 1702 independent reflections. Structure can be described as an infinite (H₂PO₄)_nⁿ⁻ corrugated chains in the a-direction. The organic groups (5-Cl-2,4-(OCH₃)₂C₆H₂NH₃)⁺ are anchored between adjacent polyanions through multiple hydrogen bonds. This compound is also investigated by IR, thermal, and solid-state, ¹³C, ³¹P MAS NMR spectroscopies.     

Corrosion Evolution of Reinforcing Steel in Concrete under Dry/Wet Cyclic Conditions Contaminated with Chloride

The corrosion evolution of rebar in concrete was monitored by electrochemical impedance spectroscopy(EIS) under dry/wet alternated accelerated corrosion test.Four stages with different dynamic characteristics were observed during the corrosion evolution.They were passive stage,local corrosion controlled by the charge transfer step,accelerated corrosion controlled by the mass transfer step,and constant rate corrosion controlled by the mass transfer step through a barrier layer.X-ray diffraction(XRD) analysis showed that the corrosion product of rebar in mortar was composed of α-FeOOH,γ-FeOOH and Fe 3 O 4.The corrosion mechanisms of all four stages were discussed and the corrosion reactions were proposed according to the corrosion product and corrosion evolution characteristics.     

Electrodeposition of CuInSe2 thin films in a glycine acid medium

CuInSe₂ polycrystalline thin films were potentiostatically electrodeposited on titanium and conducting glass substrates from an aqueous solution containing CuCl₂, InCl₃, SeO₂ in a glycine acid medium, pH around 2 adjusted with HCl. The effect of adding EDTA as a complexing agent was also studied. These films were then submitted to different post-deposition treatments: annealing at temperatures up to about 400°C in an Ar flowing stream, chemical etching in a 0.5 M KCN solution and in some cases room temperature air oxidation. The as-grown and treated layers were characterized by X-ray energy dispersive analysis, X-ray diffraction, scanning electron microscopy and photoelectrochemical studies. Annealing improves the crystallinity of electrodeposited films and the effective grain size increased, resulting in the formation of CuInSe₂ chalcopyrite structure. Photoelectrochemical measurements of the films revealed p-type behaviour, and better photoresponse was observed for the films obtained from EDTA based solutions. Room temperature air oxidation of the CuInSe₂ films improves the photocurrent response.     

Influence of structural and preparation parameters of Fe2O3/Al2O3 catalysts on rate of production and quality of carbon nanotubes

The influence of catalytic and operational parameters on the rate of growth and quality of carbon nanotubes has been investigated. A series of Fe₂O₃/Al₂O₃ catalysts prepared by different methods were investigated under conditions of synthesis of CNTs via the process of CVD of ethylene. Deposition experiments were carried out in a thermogravimetric hot-wall reactor, which enables continuous monitoring of the evolution of carbon mass with time. Controlled explosive burning (CEB) of precursor compounds was found to be the most effective method of preparation of the catalyst with respect to rate of deposition and yield of CNTs. This result has been attributed to the presence of hematite particles of small diameter on the catalyst. The presence of hydrogen in the gas feed mixture, even at small concentration, proved to be beneficial for the rate of production of MWCNTs and to result in the synthesis of CNTs of narrower diameter distribution. Yield and quality of MWCNTs depend on the concentration of the carbon source (ethylene) in the feed mixture and on temperature of deposition. Under the present experimental conditions, the optimal reaction temperature was found to be 650 °C. The products of the deposition were characterized using scanning electron microscopy and Raman spectroscopy.     

制备温度对改性二氧化铅电极材料析氧电催化性能的影响研究

通过直流阳极氧化复合电沉积法制备一种新型锌电积用β-PbO_2-MnO_2-WC-CeO_2节能催化阳极材料,采用循环伏安法(CV)和交流阻抗(EIS)研究制备温度对阳极材料析氧电催化活性的影响。循环伏安测试结果表明,温度为65℃时制备的阳极材料具有较小的阳极峰电位(Ep=1.705V)和较大的阳极伏安电荷(q*=3.367×10~(-2)C),析氧电催化活性点最多,具有较好的电催化活性。交流阻抗测试结果进一步证实65℃时制备的阳极材料在电解锌溶液中具有更小的容抗弧,表明该电极材料在工业电解锌溶液中发生析氧反应需要克服的能垒小,电极反应速率较快,电催化活性较高。     

Anticorrosion Performance of Epoxy Coatings Containing Small Amount of Inherently Conducting PEDOT/PSS on Hull Steel in Seawater

Corrosion protection of the hull steel by the conventional epoxy paint containing a small amount of commercial poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate)(PEDOT/PSS),which is one of the most popular and successful inherently conducting polymers as the corrosion inhibitor was studied.The corrosion behavior of the samples was investigated in seawater by electrochemical impedance spectroscopy and open circuit potential.Scanning electron microscopy was used to observe the surface morphology of the samples after corrosion.It was found that adding a small amount of PEDOT/PSS to the epoxy resin can significantly improve its corrosion protection.     

Hydrothermal synthesis and luminescent properties of Y2O3:Tb and Gd2O3:Tb microrods

One-dimensional (1D) Y₂O₃:Tb³⁺ and Gd₂O₃:Tb³⁺ microrods have been successfully prepared through a large-scale and facile hydrothermal method followed by a subsequent calcination process in N₂/H₂ mixed atmosphere. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (IR), thermogravimetric analysis (TGA), energy-dispersive X-ray spectra (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), photoluminescence (PL) and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples. The as-formed products via the hydrothermal process could transform to cubic Y₂O₃:Tb³⁺ and Gd₂O₃:Tb³⁺ with the same morphology and slight shrinking in size after a postannealing process. Both Y₂O₃:Tb³⁺ and Gd₂O₃:Tb³⁺ microrods exhibit strong green emission corresponding to ⁵D₄ → ⁷F₅ transition (542 nm) of Tb³⁺ under UV light excitation (307 and 258 nm, respectively), and low-voltage electron beam excitation (1.5 → 3.5 kV), which have potential applications in fluorescent lamps and field emission displays.     

Controlled hydrothermal synthesis of VO2(B) nanobelts

Large-scale VO₂(B) nanobelts have been synthesized by hydrothermal strategy via one-step method using V₂O₅ as vanadium source and C₆H₅-(CH₂)_n-NH₂ with n = 2 and 4 (2-phenylethylamine and 4-phenylbutylamine) as structure-directing templates. The composition and morphology of the nanobelts were established by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The as-obtained VO₂(B) nanobelts have a length of 3-10 μm, a wideness of 100-375 nm and a thickness of 30-66 nm.     

Performance of Ni/ScSZ cermet anode modified by coating with Gd0.2Ce0.8O2 for a SOFC

A Ni/scandia-stabilized zirconia (ScSZ) cermet anode was modified by coating with nano-sized gadolinium-doped ceria (GDC, Gd_0.2Ce_0.8O₂) within the pores of the anode for a solid oxide fuel cell (SOFC). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed in the anode characterizations. Open circuit voltages (OCVs) increased from 1.027 to 1.078 V, and the maximum power densities increased from 238 to 825 mW/cm², as the operating temperature of a SOFC with 2.0 wt.%GDC-coated Ni/ScSZ anode was increased from 700 to 850 °C in humidified hydrogen. The coating of nano-sized Gd_0.2Ce_0.8O₂ particle within the pores of the porous Ni/ScSZ anode significantly improved the performance of anode supported cell. Electrochemical impedance spectra (EIS) illustrated that the cell with Ni/ScSZ anode exhibited far greater impedances than the cell with 2.0 wt.%GDC-coated Ni/ScSZ anode. Consequently, 2.0 wt.%GDC-coated Ni/ScSZ anode could be used as a novel anode material for a SOFC due to better electrochemical performance.     

Improved photodegradation activity of TiO2 via decoration with SnS2 nanoparticles

The particles of TiO₂ modified with various amounts of SnS₂ nanoparticles (TiO₂/SnS₂) were synthesized via the hydrothermal method by reacting SnCl₄·5H₂O with thioacetamide in 5% (vol.) acetic acid aqueous solution in the presence of TiO₂. The obtained products were characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, UV–Vis diffuse reflection spectra, scanning and transmission electron microscopy. The photodegradation activities of TiO₂/SnS₂ composites have been investigated by using methyl orange as target in water under the light irradiation of 250–400, 360–600 and 400–600 nm. It was found that the photodegradation activity of TiO₂/SnS₂ composites depended on the mass ratio of SnS₂ and the wavelength of the irradiating light. The composites containing 33% SnS₂ exhibited the maximum activity under the light irradiation of 250–400 and 360–600 nm. However, the more SnS₂ in the composites, the higher activity appeared under the irradiation of 400–600 nm light. All the results reveal that the composites possess much better activity than the pristine TiO_2.     

Na2MoO4对5083铝合金微弧氧化陶瓷膜组织和耐腐蚀性能的影响

在磷酸盐电解液中添加一定浓度的钼酸钠,采用微弧氧化技术在5083铝合金表面制备出完整的氧化膜,研究了钼酸钠浓度对氧化膜性能的影响。利用SEM、EDS和XRD研究了氧化膜的表面形貌、成分和结构,并采用动电位极化曲线和电化学阻抗谱(EIS)评价氧化膜的耐腐蚀性能。结果表明:随着钼酸钠浓度的增加,氧化膜的厚度先增后减,氧化膜表面的微孔数量逐渐减少,表面更加平整致密;氧化膜主要由γ-Al_2O_3组成,钼酸钠浓度对氧化膜成分和结构影响不明显;微弧氧化陶瓷膜提高了铝合金基体的耐腐蚀性能,当钼酸盐的浓度为1.0g/L时,氧化膜具有最低的自腐蚀电流和最高的阻抗模值,表现出最优的耐腐蚀性能。     

Synthesis and crystal structure of Cu2NiO(B2O5) and Cu2MgO(B2O5)

A transport reaction synthesis technique has been used to prepare single crystals of two pyroborate compounds having the formulas Cu₂NiO(B₂O₅) and Cu₂MgO(B₂O₅). The two compounds are isostructural and crystallize in the monoclinic space group P2₁/c. Cu₂NiO(B₂O₅): a=3.2003(10), b=14.775(3), c=9.097(3), β=93.28(4), V=429.4(2) Å³, Z=4; and Cu₂MgO(B₂O₅): a=3.2401(6), b=14.790(2), c=9.147(2), β=94.88(2), V=436.7(2) Å³, Z=4. The structures of Cu₂NiO(B₂O₅) and Cu₂MgO(B₂O₅) were, respectively, refined from 804 and 1000 independent reflections to the final residuals R1=0.0366, wR2=0.0911 and R1=0.0231, wR2=0.0644. Both compounds exhibit a chevron-like structure built up of ribbons, made of edge-connected copper and nickel-oxygen polyhedra, running along the (1 0 0) direction. These ribbons are connected from one another via oxygen atoms and the cohesion of the three-dimensional network is ensured by [B₂O₅] entities. Cu in part occupies the position for Ni or Mg, so that the compounds actually are solid solution compounds. Ni or Mg atoms are octahedrally coordinated by oxygen, while the two pure Cu sites show [4] and [4+1] coordination, for Cu(1) and Cu(2), respectively. The ELNES B-K edge spectra for the two compounds support that the borate group present is [B₂O₅].     

Sonochemical synthesis,characterization, and electrochemical properties of MnMoO4 nanorods for supercapacitor applications

In this article, we reported the preparation of manganese molybdate (MnMoO₄) nanorods by a facile sonochemical method and investigated its electrochemical properties for supercapacitor applications. The microstructure, surface morphology and composition were characterized by using field emission scanning electron microscope (FE-SEM), high resolution-transmission electron microscopy (HR-TEM), X-ray diffraction analysis (XRD), Raman spectroscopy and X-ray photo electron microscopy (XPS). The cyclic voltammetry (CV) curves of sonochemically synthesized α-MnMoO₄ nanorods revealed the presence of redox pairs suggesting the pseudocapacitive nature of MnMoO₄. A maximum specific capacitance of the α-MnMoO₄ nanorods was about 168.32 F g⁻¹ as observed from the galvanostatic charge–discharge (GCD) analysis at a constant current density of 0.5 mA cm⁻². Long term cyclic stability study revealed that about 96% of initial capacitance was retained after 2000 cycles.     

Hydrothermal synthesis, characterization and magnetic properties of (N4C6H21)·(Co(H2PO4)(HPO4)2)

The title compound, (N₄C₆H₂₁)·(Co(H₂PO₄)(HPO₄)₂), was prepared hydrothermally (473 K, 10 days, autogenous pressure), in the presence of the tris(2-aminoethyl)amine as organic template. Its structure is built up from a network of four membered-rings, formed by the vertex linkages between [CoO₄] and [H₂PO₄] tetrahedra with [HPO₄] moieties hanging from the Co center. Hydrogen bonds involving the cobalt phosphate units and the triply protonated amine molecule, contribute to the stability of the structure. The IR spectrum shows bands characteristic of the (N₄C₆H₂₁)³⁺ cations and the (H₂PO₄)⁻ and (HPO₄)²⁻ phosphate anions. The UV-Visible-NIR spectrum confirms the tetrahedral coordination of Co²⁺ ions. The TGA analysis indicates that the dehydration of (N₄C₆H₂₁)·(Co(H₂PO₄)(HPO₄)₂) occurs in one step. Magnetic measurements from 4.5 to 305 K show a weak antiferromagnetic character of this compound.     

Photochemical synthesis and characterization of Bi2S3 nanofibers

Bismuth sulfide (Bi₂S₃) nanofibers have been successfully prepared by a photochemical method from an aqueous solution of bismuth nitrate (Bi(NO₃)₃) and thioacetamide (TAA) in the presence of complexing agents of nitrilotriacetic acid (NTA) at room temperature. It was found that the irradiation time, the pH of the solution, and the species of complexing agents play important roles in the morphology control of the bismuth sulfate (Bi₂S₃) nanomaterials. The nanofibers were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectra (XPS), and UV-Visible absorption spectra (UV-Vis). Probable mechanisms for the photochemical formation of Bi₂S₃ nanofibers in aqueous solutions are proposed. The photochemical method is a convenient approach for controlling the shape for other metal sulfide semiconductor nanocrystals.     

Nanosecond pulsed laser deposition of TiO2: nanostructure and morphology of deposits and plasma diagnosis

Nanostructured TiO₂ films on Si (100) substrates have been grown by nanosecond pulsed laser deposition at the wavelengths of 266, 355 and 532 nm using a Q-switched Nd:YAG laser and TiO₂ sintered rutile targets. The effect of laser irradiation wavelength, the temperature of the substrate and the presence of O₂ as background gas on the crystallinity and surface structure of deposits were determined, together with the composition, expansion dynamics and thermodynamic parameters of the ablation plume. Deposits were analyzed by X-ray photoelectron spectroscopy, X-ray diffraction, environmental scanning electron microscopy and atomic force microscopy, while in situ monitoring of the plume was carried out and characterized with spectral, temporal and spatial resolution by optical emission spectroscopy. Stoichiometric, crystalline deposits, with nanostructured morphology were obtained at substrate temperatures above 600 °C. Microscopic particulates were found overimposed on the nanostructured films but their size and density were significantly reduced by operating at short wavelength (266 nm) and upon addition of a low pressure of oxygen (0.05 Pa). The dominant crystalline phase is rutile at 355 and 532 nm. At the short irradiation wavelength, 266 nm, the preferred phase in the presence of oxygen is rutile, while anatase is preferably observed under vacuum. The narrowest size distribution and smallest nanoparticle diameters, of around 25 nm, were found by deposition at 266 nm under 0.05 Pa of oxygen.     

2D-network of inorganic-organic hybrid material built on Keggin type polyoxometallate and amino acid: [L-C2H6NO2]3[(PO4)Mo12O36]·5H2O

A new inorganic-organic hybrid material based on polyoxometallate, [L-C₂H₆NO₂]₃[(PO₄)Mo₁₂O₃₆]·5H₂O, has been successfully synthesized and characterized by single-crystal X-ray analysis, elemental analysis, infrared and ultraviolet spectroscopy, proton nuclear magnetic resonance and differential thermal analysis techniques. The title compound crystallizes in the monoclinic space group, P2₁/c_, with a = 12.4938 (8) Å, b = 19.9326 (12) Å, c = 17.9270 (11) Å, β = 102.129 (1)°, V = 4364.8 (5) Å³, Z = 4 and R₁(wR₂) = 0.0513, 0.0877. The most remarkable structural feature of this hybrid can be described as two-dimensional inorganic infinite plane-like (2D/∞ [(PO₄)Mo₁₂O₃₆]³⁻) which forming via weak Van der Waals interactions along the z axis. The characteristic band of the Keggin anion [(PO₄)Mo₁₂O₃₆]³⁻ appears at 210 nm in the UV spectrum. Thermal analysis indicates that the Keggin anion skeleton begins to decompose at 520 °C.     

NO2 gas sorption studies of Ge33Se67 films using quartz crystal microbalance

A study on the NO₂ gas sorption ability of amorphous Ge₃₃Se₆₇ coated quartz crystal microbalance (QCM) is presented. The thin films have been characterized before and after sorption/desorption processes of NO₂ by energy-dispersive X-ray spectroscopy (EDS), grazing angle X-ray diffraction (GAXRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and atom force microscopy (AFM) measurements. These studies indicated that physisorption occurs when NO₂ gas molecules are introduced into the chalcogenide film and the thin film composition or structure do not change. The mass loading due to NO₂ gas sorption was calculated by the resonator’s frequency shift. At the conditions of our experiment, up to 6.8 ng of the gas was sorbed into 200 nm thick Ge₃₃Se₆₇ film at 5000 ppm NO₂ concentration. It has been established that the process of gas molecules sorption is reversible.     

Influence of the common varistor dopants (CoO, Cr2O3 and Nb2O5) on the structural properties of SnO2 ceramics

The influence of dopants commonly used in SnO₂ varistor ceramics, such as CoO, Cr₂O₃ or Nb₂O₅, on the structural properties of SnO₂ was investigated. Several SnO₂-based ceramics containing only one of the dopants were prepared and characterized. Spectroscopic investigations [visible, near infrared (IR) and IR region] were performed to obtain information about dopants valence states inside the ceramics, as well as about their influence on electronic structure of the material. Structural properties were investigated by X-ray diffraction analysis and mechanisms of dopant incorporation were proposed. Obtained results were confirmed with results of the electrical measurements. Microstructural changes in doped ceramics were investigated by scanning electron microscopy (SEM) analysis that showed great differences in densities, grain size, and morphology of the SnO₂ ceramics depending on type of dopants and their distribution.