Papers by Keyword: Pt

Abstract: This work demonstrates a highly efficient photocathode for water splitting in neutral electrolyte. It is based on a combination of the back-field p⁺ doped Si junction, and the nanostructured NiFe layered double hydroxide as co-catalyst. This extraordinary photoelectrochemical performance is primarily attributed to the catalyst-induced dramatic increase in active surface sites, and the suppression of hole recombination. Following the deposition of Pt nanoparticles between the Si junction and NiFe layered double hydroxide, the platinized photocathode (n⁺pp⁺ Si/Pt/NiFe LDH) exhibited an excellent photocurrent density of -4.98 mA/cm² at 0 V versus the standard reference (RHE) in 0.5 M Na₂SO₄ electrolyte. The superior quality of our cathode is demonstrated by the magnitude of the photoinduced current density (after dark current correction), which approaches the theoretical maximum. This achievement is attributed to the successful construction of built-in electric fields.

Abstract: Titania pillared clay membranes exhibit unique charge characteristics which are dependent on the solution pH. Doping of such membranes with precious metal like Pt induces a positive charge on the surface of the membranes, thus increasing its resistance against fouling. X-ray Diffraction (XRD) and Fourier Transform Infra-Red Spectroscopy (FT-IR) confirm the complete intercalation of anatase titania in the interlayer spaces of Montmorillonite in the present work. These membranes efficiently removed 83% of the dye from the real textile effluent in a one filtration cycle.

Abstract: The influence of ZnO and Pt nanoparticles’ suspensions (5 mg/kg of soil) on the yielding capacity and fruit quality of Cucumis sativus L. was studied. We found out that the soil amended with ZnO nanoparticle suspension enhanced cucumber yielding capacity by 36 %, and the fruits had more carotene, zinc and iron compared to the control. The soil amended with Pt nanoparticles did not influence cucumber yielding capacity, and the fruits contained more carotene and zinc. ICP-MS results showed that nanoparticles’ influence at the concentration under study did not result in accumulation of ZnO and Pt nanoparticles in fruits.

Abstract: The multilayer films [Al₂O₃/t_Co Co/t_Pt Pt]_N, produced by sequential deposition of Co and Pt on alumina consist in layers of CoPt alloyed nanoparticles. They show perpendicular magnetic anisotropy (PMA) below a freezing temperature T_f, an asperomagnetic-like phase below that temperature, and hard ferromagnetic ordering below a transition temperature T₁ < T_f. A single layer granular film (N = 1) with deposition thicknesses t_Co=0.7 nm, t_Pt=1.5 nm and particle diameter of 3 nm is presently studied. SQUID magnetometry shows that a single layer presents the three phases as well. Para-, aspero-and ferromagnetic phases are observed upon lowering the temperature, with transition temperatures T_f ≈ 375 K and T₁ ≈ 200 K, respectively. In addition, the PMA persists, proving that there is no interlayer coupling in the multilayer system. SQUID results also reveal a core-shell structure in the CoPt nanoparticles.

Abstract: Oxygen adsorption, aluminium segregation and interface adhesion on the surface of NiPtAl and MCrAlY bond coats (BC) in EB-PVD TBC system were investigated using first-principles calculations within the density functional theory (DFT). Examination of oxygen adsorption and aluminium segregation indicated that the addition of Pt always obstructed the growth of alumina. In addition, NiPtAl, as bond coats in EB-PVD TBC System, had less lattice variation and stronger interface adhesion than MCrAlY when alumina was produced. It is found that Pt is an important factor that affects the Al₂O₃ growth in thermal barrier coating. It is proved that Pt improves the bonding performance of Al₂O₃ and lifetime of thermal barrier coating. This offsets the high cost of Pt in industry application.

Abstract: Pure SnO₂ and Pt doped SnO₂ (0≤Pt≤10wt.%) ceramics have been successfully fabricated in the form of pellet by sintering at 1000 °C for 3 h. The resistance of the samples in air and in reducing gases (200 ppm H₂ and 200 ppm CO) was determined by measuring current – voltage (I-V) characteristics via two-probe method between 150 to 450 °C. All samples show a decrease in resistance with an increase in temperature both in air and in gases. However, the values of resistance in gases are lower compared when the same samples were in air, due to gas molecules reactions with surface oxygen species which affect potential barrier to decrease and causes resistance to reduce. The resistance of the doped samples also increased by 279 - 1226% with an increase in Pt doping in SnO₂, due to Pt surface states density.

Abstract: A new sensor with Pt and Ag mixture paste on the surface to act as the sensing electrode (Ag) and catalyst (Pt) to oxidized SO₂ to SO₃ for sulfur dioxide was fabricated. The effect of auxiliary phase on the sensing properties has been investigated and the device with auxiliary phase showed better performance and the effect of operating temperature has also been studied. It shown that 500°C would be more suitable than 600°C for the device gas test.

Abstract: With the feathered development of communication and networks,the needs for the communication cable is highly increased,while the assurance of the communication cable’s quality is an important work for every cable factory to slove.The major research of this project is aim at the problems about the dynamic testing and the uniformity of cable insulation layer,and then the online test control system were designed.The control is mainly use OMRON's CS1G-H PLC as the central control system, at the same time control system uses touch-screen to realize the man-machine dialogue,which can effectively monitor the operational status of the equipment.Through the programming, simulation, simulation experiment for this system in the laboratory,proved that this system can be in motion, achieve the desired functionality. At the same time this system can be used for the promotion and use.

Abstract: A novel fly ash cenospheres supported Pt–BiVO₄ composites (Pt–BiVO₄/FACs) photocatalysts were prepared by modified metalorganic decomposition process, followed by photochemical reduction. The composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), and UV–vis diffused reflectance spectroscopy (DRS) techniques. The results indicate that the visible light absorption of the Pt–BiVO₄/FACs composite is greatly enhanced. The Pt element is present in the metallic form and disperses in the composite samples. Photocatalytic activities of the Pt–BiVO₄/FACs composites were evaluated by the methylene blue (MB) degradation under visible light irradiation. The results indicate that the photocatalytic efficiency is significantly improved after the Pt species was loaded and the 2 wt% Pt-loaded composite showed the highest photocatalytic activity.

Abstract: Low-temperature fuel cells have been attracting more and more attentions for the direct conversion of chemical energy into electricity. Efficiencies of fuel cells to a great extent depend on the activity of the catalytic platinum and its alloys. Increasing the reaction surface area and decreasing the diameter of platinum particles can enhance the activity of the platinum. In this paper, we report a platinum catalyst supported on porous carbon nanofibers. Two kinds of PAN terpolymers with various molecular weights of 15 kDa (PAN-1) and 30 kDa (PAN-2) were first prepared by aqueous precipitation polymerization. The mixtures of PAN with various molecular weights and PMMA were then electrospun, stabilized and carbonized to provide the porous carbon nanofibers. It was found that the PAN with lower molecular weight results in the even fibrous surface and thick diameter, indicating a stable spinning process. Moreover, the PAN-based carbon nanofibers were immersed into a platinum complex solution to support the platinum positive ions. After calcination, the platinum ions deposited on the carbon nanofibers were converted into nanoplatinum particles to provide the platinum catalyst supported on the porous carbon nanofibers.