• Resources Recycling
• /
• v.27 no.2
• /
• pp.32-37
• /
• 2018

This study was conducted as a preliminary study for the recycling of palladium and palladium oxide. In this study, thermodynamic equations for the formation of palladium oxide (PdO) are established. Palladium chloride is dissolved into hydrochloric acid to generate a palladium chloride solution. Nanosized palladium oxide powder with an average particle size below 30 nm were generated from this raw material solution by means of a spray pyrolysis process. The palladium oxide particles were composed of a single solid crystal. The results of XRD analysis showed that only a PdO phase of the generated powder was formed. And, the specific surface area of the generated palladium powder was approximately $32m^2/g$.

• Archives of Pharmacal Research
• /
• v.15 no.4
• /
• pp.336-342
• /
• 1992

Ten [$Pd^{II}$(dicarboxylato)(1, 2-diaminocyclohexane)] complexes were prepared after the antitumor-active Pt(II)1, 2-diaminocyclohexane complexes as the cisplatin analogues of palladium series. They were characterized by means of elemental analysis, IR and NMR spectroscopy. As a result, the dicarboxylate ligands were conformed to be chelated with Pd(II) within the scope studied. The stability differences beween the dicarboxylato complexes according to the chelate ring size could not be differentiated due to generally lower thermodynamic stability of the dicarboxylato Pd(II) complexes.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.139.1-139.1
• /
• 2013

Graphene and graphene oxide (GO) have been modified with palladium nanoparticles (Pd NPs) to develop high performance catalysts for the Sonogashira cross coupling reaction. To understand catalytic performance of Pd NPs on graphene (Pd/G) and Pd NPs on GO (Pd/GO), we monitored their morphological and electronic structural changes before/after Sonogashira reaction using FT-IR, XRD, XPS, and XAFS. Here, we demonstrate that both Pd/G and Pd/GO show high catalytic efficiency toward the Sonogashira reaction, but only Pd/GO revealed excellent recyclability. The remarkable catalytic efficiency of both catalysts is attributed to the high degree of the Pd NP dispersions on supports and thus smaller Pd NPs can provide highly reactive low coordinated Pd atoms. However, we attributed the excellent recyclability of Pd/GO to the presence of oxygen functionalities on GO, which can provide nucleation sites for the detached Pd atoms during the Sonogashira reaction and prevent agglomeration of the Pd NPs since the oxygen functional groups are very reactive to mobile Pd adatoms.

• Macromolecular Research
• /
• v.17 no.12
• /
• pp.987-994
• /
• 2009

Palladium nanoparticles having cubic silsesquioxanes (POSS) (Pd-POSS) were produced by the reaction of palladium (II) acetate and octa(3-aminopropyl)octasilsesquioxane octahydrochloride (POSS-${NH_3}^+$ in methanol at room temperature. Functionalized multiwalled carbon nanotubes (MWNT-COOH) were prepared by acid treatment of pristine MWNTs. The hybrid nanocomposites of Pd-POSS and MWNT-COOH (Pd-MWNT nanocomposites) were synthesized by self-assembly method via ionic interaction between positively charged Pd-POSS and negatively charged MWNT-$COO^-$. The spherical aggregates of Pd-POSS with a diameter of 40-60 urn were well attached to the surfaces of MWNT-COOH on Silicon wafer. The composition, structure, and surface morphology of Pd-MWNT nanocomposites were studied by UV-vis spectrophotometer, energy dispersive spectrum (EDX), scanning electron microscopy (SEM), and atomic force microscope (AFM).

• Resources Recycling
• /
• v.14 no.1
• /
• pp.55-63
• /
• 2005

This study investigated the electrochemical recovery of palladium in a HCl solution that is used for palladium leaching. The high acidity of HCl solution and the low concentration of Pd ions increased the cathodic overpotential and reduced the limiting current density. Lowering the current density produced dense deposits; however, they were under high tensile stress. Raising the temperature affected both the densification and the stress, which enabled the attainment of dense Pd deposits under low stress. Lowering the current density and raising the temperature up to 70$^{\circ}C$ was recommended for the recovery of palladium as sound bulk Pd deposits. Current efficiency was over 85% at the initial stage of recovery may decrease the current efficiency, since a low Pd ion concentration results in a low limiting current density.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.12
• /
• pp.3745-3748
• /
• 2010

Pd(II) p-tolylamide Pd(2,6-$(Ph_2PCH_2)_2C_6H_3$)(NH($C_6H_4Me$-p)) (1) was metathetically prepared by the reaction of Pd(2,6-$(Ph_2PCH_2)_2C_6H_3$)Cl with NaNH($C_6H_4Me$-p). Treatment of 1 with carbon dioxide affords the palladium(II) carbamate Pd(2,6-$(Ph_2PCH_2)_2C_6H_3$)(OC(O)NH($C_6H_4Me$-p)) (2), quantitatively. Complex 2 reacts with HX (X = Cl, OTf) to give Pd(2,6-$(Ph_2PCH_2)_2C_6H_3$)X, $NH_2$(p-Tol) and $CO_2$. Reaction of the palladium(II) carbamate with MeI produced Pd(2,6-$(Ph_2PCH_2)_2C_6H_3$)I along with generation of methyl N-tolylcarbamate MeOC(O)NH($C_6H_4Me$-p), exclusively.

• Journal of the Korean Chemical Society
• /
• v.26 no.1
• /
• pp.31-35
• /
• 1982

Novel palladium(II) complexes of the type Pd(IBA-NH)(IBA-NH') and Pd(IBA-NR)2, where IBA-NH and IBA-NR (R: methyl, ethyl, n-propyl, n-butyl, benzyl) represent isonitrosobenzoylacetone imine and its N-alkyl derivatives respectively, have been prepared. The ir, nmr, and electronic spectra of the palladium(Ⅱ) complexes have been studied. It has been determined that the isonitroso group of IBA-NH coordinates to palladium through the oxygen to form 6-membered chelate ring and that of IBA-NH' coordinates to palladium through the nitrogen to form 5-membered ring in square-planar Pd(IBA-NH)(IBA-NH') and it also has been determined that the isonitroso groups of two IBA-NR coordinates to palladium through the nitrogen to form 5-membered rings in square-planar Pd$(IBA-NR)_2$. The coordination manner of the ligands is similar to that of isonitrosoacetylacetone imines obtained by Bose, et $al.^5$.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2003.11a
• /
• pp.642-647
• /
• 2003

Palladium is widely used for several applications and recovery of palladium from secondary sources becomes increasingly important since palladium is one of maldistributed platinum group metals. Electrochemical recovery of dense palladium metal sheet from Pd leaching solution is a simple and easily controlled method. The surface morphology of the recovered Pd metal was significantly affected by current density and temperature. Dense deposit morphology was in higher stress state regardless of preparation condition under $55^{\circ}C$. Rising temperature up to $70^{\circ}C$ had a stress releasing effect besides densification of Pd deposit.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.11
• /
• pp.1902-1909
• /
• 2007

This account reports an overview of our findings in homogeneous Pd-catalyzed reactions. Herein we describe the new design in reactions of Group 14 element compounds and in homogeneous nanosize Pd catalysts. In the early stages of our study, we developed Pd-catalyzed transformations of allylic esters with disilanes, silylcyanides and acylsilanes to the corresponding silylation, cyanation and acylation products, respectively. We also developed a Pd-catalyzed three component coupling reaction of Group 14 element compounds involving 1,3-diene and acid chlorides to form β,γ-unsaturated ketone as a single product. Recently, we focus our attention on modifying the catalytic environment by nanosize Pd in order to improve the performance of Pd catalysts. These nanosystems realize efficient catalytic environment with remarkable enhancement in catalytic activity and unprecedented selectivity.

• Korean Journal of Materials Research
• /
• v.24 no.10
• /
• pp.532-537
• /
• 2014

In this study, highly sensitive hydrogen micro gas sensors of the multi-layer and micro-heater type were designed and fabricated using the micro electro mechanical system (MEMS) process and palladium catalytic metal. The dimensions of the fabricated hydrogen gas sensor were about $5mm{\times}4mm$ and the sensing layer of palladium metal was deposited in the middle of the device. The sensing palladium films were modified to be nano-honeycomb and nano-hemisphere structures using an anodic aluminum oxide (AAO) template and nano-sized polystyrene beads, respectively. The sensitivities (Rs), which are the ratio of the relative resistance were significantly improved and reached levels of 0.783% and 1.045 % with 2,000 ppm H2 at $70^{\circ}C$ for nano-honeycomb and nano-hemisphere structured Pd films, respectively, on the other hand, the sensitivity was 0.638% for the plain Pd thin film. The improvement of sensitivities for the nano-honeycomb and nano-hemisphere structured Pd films with respect to the plain Pd-thin film was thought to be due to the nanoporous surface topographies of AAO and nano-sized polystyrene beads.