Papers by Keyword: Palladium

Abstract: The crystal structure of the new ternary aluminide Sc_1.33Pd₃Al₈ was refined by the Rietveld method from X-ray powder diffraction data. It crystallizes with a Gd_1.33Pt₃Al₈-type structure: hR51-14.00, R-3m, a = 4.29142(4), c = 38.1638(4) Å, R_B = 0.0344. The main feature of the structure is the statistical distribution of Sc atoms and Al₃ triangles within atomic layers of composition Sc₂Al₃ (Sc_0.67Al within the translation unit here), which is likely to correspond to stacking disorder of ordered layers. During the final cycles of the refinement, the occupancies of the corresponding sites were fixed at occ. = 2/3 for Sc in Wyckoff position 6c and occ. = 1/3 for Al in 18h. The unit cell of Sc_1.33Pd₃Al₈ contains six Sc_0.67Al layers, nine Pd and eighteen Al atom layers along the crystallographic direction [001]. Together with the structure types Tb_0.67PdAl₃, Y₂Co₃Ga₉, Sc_0.67Fe₂Si₅, Er₄Pt₉Al₂₄, Yb_0.67Ni₂Al₆, and ErNi₃Al₉, the structure type Gd_1.33Pt₃Al₈ forms a family of intergrowth structures built up of three kinds of similar monoatomic layer.

Abstract: In this work, the preparation of graphene by chemical oxidation reduction method and a series of chemical reactions to get graphene oxide, with the preparation of graphene composites by simply chemical reduction method for the preparation of palladium/graphene composites. Through the chemical reduction method, the small size of Pd nanoparticles is acquired by controlling the content of reducing agent. The Pd nanoparticles on graphene surface is 10nm size and evenly distributed. Pd2+ adsorption on graphene surface and in situ were partially reduced to Pd to Pd2+ nanoparticles by the reducibility of graphene. In the process, the graphene was reduced to graphene and the final compound was thinner and more transparent than the pre-experiment oxide. The oxygen-containing functional groups on the surface of the graphene have influence to the nucleation and growth of metal nanoparticles and KI can control the morphology and size of nanoparticles. The particle size and dispersion uniformity have great influence on the catalytic performance of composites, the smaller particles have better catalytic performance. Keywords:palladium, graphene composites, nanoparticles

Abstract: Bulk β-PdBi₂ layered material is known as a low-temperature superconductor. Recently, ultrathin films of this material consisting of dozens of triple layers were grown by molecular beam epitaxy and demonstrated structural, electronic and superconducting properties similar to those of bulk crystals. In this paper, we showed that thin film of β-PdBi₂ can be grown by alternative palladium and bismuth deposition and its electrical conductance was investigated at room temperature in comparison with the conductivity of bulk β - PdBi₂.

Abstract: Palladium (II) complex containing picoline thiourea (Pd-PTu) was prepared by reacting bis (benzonitrile) palladium (II) chloride (Pd-PhCN) with N’-2-(5-picolyl)-N-4-bromobenzoylthiourea (PTu). All synthesized compounds have been characterized via several selected typical spectroscopic and analytical techniques namely elemental analysis, Infrared (IR) spectroscopy, Ultraviolet-visible (UV-Vis) spectroscopy, Nuclear Magnetic Resonance (¹H and ¹³C NMR) and gas chromatography-flame ionization detector (GC-FID). For Pd-PTu, IR spectrum showed significant shift in the ν (C=N) on the pyridine ring and ν (C=S) stretching vibration at around 30cm^-1 compared to the free ligand. The finding indicated that the expected coordination of ligand to the palladium metal centre took place via N and S atoms. The catalytic reaction was monitored using GC-FID with conversion of 83.81 %, proved that Pd-PTu can be used as an ideal homogenous catalyst in any Heck cross-coupling reactions in the near future.

Abstract: This study aims to describe the influence of adding graphene oxide to TiO₂-noble metal (Me=Ag, Au or Pd) composite nanoparticles on their bioactivity (formation of RGO/TiO₂-Me nanocomposite system). The obtained nanocomposite flakes and reference TiO₂-Me nanoparticles were characterized using SEM, HRTEM and XPS spectroscopy, N₂ sorption analysis and helium pycnometer. The analysis of the antibacterial properties of synthesized nanocomposites revealed a growth inhibiting effect of TiO₂-Ag particles on gram positive bacteria such as: Staphylococcus aureus, Sarcina lutea and Bacillus subtilis. In the case of nanocomposite flakes containing RGO the visible changes in bacteriostatic properties were observed, including unexpected reversal of the antimicrobial activity of silver-containing nanoparticles into the stimulation of growth of applied bacterial strains. The stimulation of growth was not observed for TiO₂-Au and Pd nanoparticles deposited on the surface of RGO.

Abstract: An electrochemical method for determination of the platinum and palladium was suggested and developed in this study. The effect of accompanying elements on the electrochemical oxidation processes of platinum and palladium has been described. It has been shown that the determination of platinum and palladium is possible only after removal of sample components.

Abstract: Anodic stripping voltammetry, a classical electroanalytical method has been optimized to analyze trace Pd (II) in tailings. The authors identified the registration conditions in the determination of the analytical signal Pd (II): the composition of background electrolyte and the electrolysis potential. The electroanalytical approaches with an unmodified carbon electrode were used. The use of stripping voltammetry applied to the assessment of the palladium content in geological objects was demonstrated.

Abstract: In order to enhance catalytic properties of palladium or gold/palladium alloy on polyaniline surface, highly pure PANI nanofibers doped with phosphoric acid were synthesized via chemical self-assembled method. Its general morphology was observed by scanning electron microscopy analysis. The deposition of palladium or gold/palladium alloy on PANI nanofibers was accomplished through reducing reaction of PdCl₂ or PdCl₂/HAuCl₄ in aqueous solution by NaBH₄. Pd/PANI nanofibers or Au/Pd/PANI nanofibers have been evaluated for catalytic activity toward formic acid oxidation reaction. Palladium/PANI nanofibers or palladium/gold/PANI nanofibers on glass carbon electrodes exhibit effective electro-catalytic activity since the PANI nanofibers play excellent promoting role.

Abstract: For materials, science it is important to study the structure and behavior of matter at the deepest level. Currently, modern microscopes allow one to see the atomic structure of matter. Materials should be prepared in a special way, for research in the microscope, but thus the natural structure of the material may changed. Especially, the processes at the atomic level are difficult to explore. In a computer model of matter, one can account the properties of atoms and even its electron structure. In this paper, by molecular dynamics method the structure and evolution of the palladium and its compounds with hydrogen are investigated. In the work equilibrium structure of the crystal lattice of palladium was obtained and determined the equilibrium lattice parameter at different temperatures. The behavior of the hydrogen atom inside the crystal lattice of palladium was studied. The structural and diffusion properties system palladium-hydrogen were obtained

Abstract: Abstract In this work, the low-temperature H₂-sensing properties of palladium (Pd) and palladium oxide (PdO) nanoparticles decorated titanium dioxide (TiO₂) thin film were studied. The TiO₂ thin films were prepared by the dc reactive magnetron sputtering. The Pd and PdO nanoparticles were sputtered on the top surface of TiO₂ surface in order to enhance the sensitivity to the H₂ gas. Morphologies, crystal structures, and chemical element of the examiner samples were investigated by the field-emission scanning electron microscopy (FE-SEM), grazing-incident X-ray diffraction (GIXRD), and X-ray photoelectron spectroscopy (XPS), respectively. The effects of the Pd and PdO nanoparticles on H₂-sensing performance of TiO₂ were investigated over a low concentration range of 150-3,000 ppm H₂ at 50-250°C-operating temperatures. This result exhibited that the PdO decorated on TiO₂ surface showed very high response to H₂ at a low operating temperature of 150°C.