查看更多>>摘要：Chemically-modified Indium Tin Oxide (ITO) coated glass substrates were fabricated by depositing Nafion thin films doped with tris (2,2'-bipyridyl) ruthenium(II) dichloride hexahydrate via drop coating deposition technique. The Nafion volume concentration in the film is 1% (v/v) and the mediator concentration is 5 mg per 1 mL Nafion. The chemically-modified electrodes were characterized by cyclic voltammetry (CV) and were used as working electrodes to detect varying concentrations of copper (Cu2+) and zinc (Zn2+) in a 0.1 M NaCl supporting electrolyte solution via Anodic Stripping Voltammetry (ASV). Cu2+ and Zn2+ ions were successfully determined by ASV. The limits of detection for Cu2+ and Zn2+ were 0.1 ppm and 0.7 ppm, respectively. The modified electrodes were used to determine the presence of Cu2+ and Zn2+ in different real water samples. The presence of Cu2+ was successfully determined in deep well, lake, and tap water samples, while the presence of Zn2+ was successfully determined in sea and tap water samples. Atomic Absorption Spectroscopy (AAS) results confirm the presence of Cu2+ and Zn2+ in the samples.
查看更多>>摘要：Functionalization of carbon nanotubes proceeds by using atmospheric pressure non-thermal plasma treatment, where NH3 is used as nitrogen sources which is excited either by alternating currents (AC) or direct currents (DC). The content and species of the functional groups are analyzed by XPS which displays that heteroatom content increases 1.6 at.%, the main nitrogen groups are pyridinic nitrogen (N-6) and amino (-NH2), and HO-C=O, C=O and C-OH surface groups are also incorporated. The supercapacitive performance of the pristine CNTs, CNT-DC and CNT-AC electrodes are measured and the specific capacitance of CNTs is increased after plasma treatment, which indicate that the surface functionalization facilitate the improvement on supercapacitive properties.
查看更多>>摘要：Laser cutting is the popular unconventional manufacturing method widely used to cut various engineering materials. In this work CO2 laser cutting of AISI 314 satinless steel has been investigated. This paper focus on the investigation into the effect of laser cutting parameters like laser power, assist gas pressure, cutting speed and stand-off distance on surface roughness, hardness and kerf dimensions like kerf width, kerf ratio and kerf taper in CO2 laser cutting of AISI 314 stainless steel.
查看更多>>摘要：This manuscript reports the use of TiO2-BaTiO3 composite films as a photoanode in dye-sensitized solar cell (DSSC). The influence of BaTiO3 content on the performance parameters of the DSSC has been investigated. The composite has been prepared on ITO glass substrate via sol-gel assisted with spin coating technique. The XRD analysis reveals that the sample is crystalline with the phase of BaTiO3 and anatase TiO2. From the FESEM observation, it was found that the pure sample contains bigger pores compared with the other samples prepared with various BaTiO3 contents. The samples become more compact as the content of BaTiO3 increases. The samples absorb more light in ultraviolet (UV) region than visible region. The area of absorption window varies with BaTiO3 content. The device utilizing the sample with 0 and 6 wt.% BaTiO3 demonstrated the lowest leak current. The device utilizing pure sample produced the highest. of 0.18%. This is due to this device utilized the sample with highest porosity, lowest leak current and charge transfer resistance, R-ct.
Fernandez, CarlosSingh, N. K.Yadav, RituYadav, M. K....
7页
查看更多>>摘要：Some ternary ferrites having composition CoxNi1.5-xFe1.5O4 (0.0 <= x <= 1.25) have been synthesized by NH4OH co-precipitation method at 11.5 pH. Materials, so obtained, were tested for their electrocatalytic properties towards oxygen evolution reaction (OER) in the form film on Ni-support in alkaline solution. The study showed that the electrocatalytic properties the material increased with partial substitution of Co for Ni in the base oxide (Ni1.5Fe1.5O4). The value being highest with 1.25 mol Co-substitution. At E = 850 mV vs Hg/HgO in 1M KOH at 25 degrees C, the electrode showed apparent current density 137.1 mA cm(-2), which is about 2.5 times higher than the base oxide. The Tafel slope values were ranged between 53-90 mV decade-1. A pair of redox peak, an anodic (E-Pa = 522 +/- 28 mV) and corresponding cathodic (E-Pc= 356 +/- 9 mV), was observed in the cyclic voltammetry (CV) study of the material. The thermodynamic parameters namely, standard apparent electrochemical enthalpy of activation (Delta H-el degrees(not equal)), standard enthalpy of activation (Delta H degrees(not equal)) and standard entropy of activation (Delta s degrees(not equal)) for the oxygen evolution reaction (OER) have also been determined by recording anodic polarization curve in 1M KOH. The value of Delta H degrees(not equal) was observed to be almost similar with each oxide electrode. The Delta s degrees(not equal) values were highly negative and ranged between similar to -165 and similar to -207 J deg(-1) mol(-1). Phase and morphology of materials have been investigated by using physical techniques X-ray diffraction, infrared spectroscopy (IR) and scanning electron microscope (SEM), respectively.
查看更多>>摘要：A potential hydrogen source generated from milled Li-Si-AlCl3 composite was evaluated in this paper. The composite exhibits good hydrogen generation performance in water at 313-343 K, whereas pure silicon powder cannot continuously react with water under similar conditions. The hydrogen yield reaches 1300 mL hydrogen/g within 20 min, and the highest hydrogen generation rate is higher than 1200 mL hydrogen/g min within the first minute of hydrolysis. The hydrogen generation performance increases with increasing concentrations of lithium and aluminum chloride. Microstructure analysis indicates that silicon activity increases due to decreased particle size and distribution of lithium and aluminum chloride into silicon matrix during milling. The hydrolysis of the additives generates heat and alkaline hydrolysis byproducts, thereby stimulating the hydrolysis rate of silicon in the micro area. Therefore, the hydrolysis of silicon in water may act as a potential hydrogen source for portable micro fuel cells.
查看更多>>摘要：Integrated Planar Solid Oxide Fuel Cells (IP-SOFC), which utilise a Ni/YSZ based anode, have been operated under direct hydrogen-methane mixture fuel injection at 900 degrees C. This process has shown some disadvantages in fuelling to the IP-SOFC; producing carbon deposition from the methane in the fuel mixture, causing direct structural damage to the IP-SOFC surface and blocking the area of activation for reaction processes and reducing the performances. These factors were shown to adversely affect the performance of the IP-SOFC over time. The aim of this paper is to calculate the amount of carbon deposited through the use of temperature programmed oxidation (TPO). In addition, the distribution of carbon is studied and analysed on all parts of the IP-SOFC cells. The results show that both amorphous and graphitic carbon were formed causing microstructural damage thereby reducing the cell performance. Furthermore, the reaction temperature was demonstrated to increase the total amount of carbon deposition.
查看更多>>摘要：This study was undertaken to investigate the structural, electrical and electrochemical properties of Fe3+ substituted Mg0.55Si1.9Al0.1(PO4)(3) compound synthesized by water-based sol-gel technique. X-ray diffraction showed that the compound crystallized in monoclinic crystalline phase with a space group of P1 2(1)/c1. The sample sintered at 850 degrees C exhibited the highest conductivity of 1.42 x 10(-6) S cm(-1) at 373 K since it contained the highest number of mobile ions. It also exhibited the highest value of ion mobility, mu of 1.13 x 10(-11) cm(2) V-1 s(-1) at ambient temperature which was attributed to the optimum size of migration channel as indicated by its unit cell volume. Linear sweep voltammetry result showed that the Mg0.55Si1.9Al0.1Fe0.1(PO4)(3) was electrochemically stable up to 3.0 V. Meanwhile, its ionic transference number of 0.99 suggested that the majority of the mobile charge carriers were mainly to ions, expected to be Mg2+ ions.
查看更多>>摘要：Solvent free efficient green glycolysis of Polyethylene terephthalate waste, PET, in this respect, PET waste was subjected to depolymerization with propylene glycol in the presence of manganese acetate as a catalyst, the product is Bis-(3-hydroxy-propyl)terephthalate, BHPT, as non-ionic surfactant was separated, characterized by FT-IR and 1HNMR, BHPT was evaluated as corrosion inhibitor for steel in the presence of 1.0 M sulfuric acid by chemical and electrochemical methods, the corrosion inhibition efficiency increase with inhibitor concentration and decrease with temperatures, the galvanostatic polarization curves indicate that the BHPT, compound act as mixed inhibitor, the impedance of the inhibited solution has increased with the increase in the concentration of the inhibitor. the inhibition due to adsorption of the inhibitor molecules on the steel surface, the adsorption obey Langmuir adsorption isotherm. Thermodynamic parameters were computed and discussed, Scanning electron microscope (SEM) was used to study the surface morphology of steel in absence and presence of the used inhibitor, hydrogen evolution techniques was used to evaluate the inhibition efficiency of the BHPT inhibitor compound. the data obtained from different techniques are in good agreement to each other and show the BHPT, surfactant derived from PET, waste considered as good corrosion inhibitor for steel in sulfuric acid.
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