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The electrocatalytic activity of electrode materials synthesized by anodic selective dissolution of Ag–Pd alloys based on silver (4 and 8 at % Pd) was studied. Kinetic regularities of formic acid electrooxidation on palladium and anodically modified Ag–Pd alloys in an acidic sulfate solution have been established. The process includes the diffusion of HCOOH, its dissociative chemisorption, and irreversible ionization of atomic hydrogen. The conditions for formic acid anodic oxidation on Pd and Ag–Pd alloys were determined depending on the composition of the electrode system and the mode of preliminary electrochemical modification (selective dissolution) of the alloy using transient electrochemical measurements. The role of the surface development of an alloy in the kinetics of anodic degradation of formic acid was revealed. It was shown that the selective dissolution of Ag–Pd alloys contributes to a noticeable increase in the rate of the kinetic stage of atomic hydrogen ionization. A necessary condition for the activation of the anodically modified alloy in relation to the electrooxidation of HCOOH is the excess of both critical parameters (charge and potential) corresponding to the onset of morphological development and phase transformations in the surface layer of the Ag–Pd systems. [ABSTRACT FROM AUTHOR]

High-temperature gas-cooled reactors (HTGRs) have garnered considerable interest due to their superior efficiency and inherent safety. This study systematically investigates the interaction between silver-palladium (Ag-Pd) alloy and silicon carbide (SiC) coating in tri-structural isotropic (TRISO) particles of HTGRs, focusing on the potential release of radioactive Ag-110 m through SiC cladding. Operating temperatures ranging from 800–1100 °C were examined to understand the mechanisms of Ag-Pd migration in SiC. Advanced techniques like transmission electron microscopy (TEM), focused ion beam (FIB) coupled with 3D visualization and scanning precession electron diffraction (SPED) integrated with machine learning were employed to identify two pathways of Pd-assisted Ag migration: (1) (Pd,Ag) 2 Si and (Pd,Ag) 3 Si acting as migration channels, and (2) Pd-rich phases increasing SiC disorder, enhancing Ag diffusion. Significantly, a carbon barrier formation above 1000 °C was observed, which inhibits Ag-Pd/SiC interaction. These findings offering new insights for predicting nuclear reactor lifespan and data support to optimize TRISO particles' structural design. [Display omitted] [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of repeated casting and heat treatment on the corrosion resistance of a commercial Ag-Pd-Cu-Au alloy as evaluated by electrochemical techniques. After repeated casting, the fifth cast of the Ag-Pd-Cu-Au alloy exhibited dramatic degradation of properties, although upon heat treatment, this corrosion resistance did improve. Despite the improvement by heat treatment, after five castings, this alloy may not have satisfactory hardness for clinical use. These results of this study demonstrate that, up to the fourth cast and heat treatment, the Ag-Pd-Cu-Au alloy has acceptable corrosion resistance and hardness. [ABSTRACT FROM AUTHOR]

The reactions between palladium (Pd), palladium-silver alloy (Pd-Ag) and silicon carbide (SiC) from 1200 °C to 1400 °C have been studied to investigate the impact of liquid phases on reaction products formation. The liquid phases were generated in Pd/SiC reactions at 1400 °C and in Pd-Ag/SiC reactions above 1300 °C. An increase in the amount of liquid associated with higher temperatures or Ag presence strongly affected the reaction mechanism and was responsible for the inhomogeneous dissolution of SiC grains and grain boundaries by Pd-rich phase at reaction front. This study helps understand Pd's role on Ag release through SiC layer in Tri-structural isotropic (TRISO) fuel particles. [ABSTRACT FROM AUTHOR]

Selected results of investigations focused on the changes to some mechanical properties of palladium and several palladium-based alloys caused by exposure to hydrogen have been collected and presented. The findings indicate that the mechanical properties of pure palladium are highly susceptible to alteration upon exposure to hydrogen. In the cases of alloying palladium with silver and copper, the alloys, as compared to palladium, appear to resist changes to mechanical properties. In the case of alloying palladium with manganese, the interesting order–disorder phenomenon plays an important role on the effects of hydrogen exposure on their mechanical properties. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Atomically precise thiolate-protected coinage metal nanoclusters and their alloys are far more numerous than their selenium congeners, the synthesis of which remains extremely challenging. Herein, we report the synthesis of a series of atomically defined dithiophosph(in)ate protected eight-electron superatomic palladium silver nanoalloys [PdAg20{S2PR2}12], 2a–c (where R = OiPr, a; OiBu, b; Ph, c) via ligand exchange and/or co-reduction methods. The ligand exchange reaction on [PdAg20{S2P(OnPr)2}12], 1, with [NH4{Se2PR2}12] (where R = OiPr, or OnPr) leads to the formation of [PdAg20{Se2P(OiPr)2}12] (3) and [PdAg20{Se2P(OnPr)2}12] (4), respectively. Solid state structures of 2a, 2b, 3 and 4 unravel different PdAg20 metal frameworks from their parent cluster, originating from the different distributions of the eight-capping silver(I) atoms around a Pd@Ag12 centered icosahedron with C2,D3,Th and Th symmetries, respectively. Surprisingly ambient temperature crystallization of the reaction product 3 obtained by the ligand exchange reaction on 1 has resulted in the co-crystallization of two isomers in the unit cell with overall T (3a) and C3 (3b) symmetries, respectively. To our knowledge, this is the first ever characterized isomeric pair among the selenolate-protected NCs. Density functional theory (DFT) studies further rationalize the preferred geometrical isomerism of the PdAg20 core. Atomically and structurally precise silver nanoclusters hold great potential for catalytic and optoelectronic applications. Here, the authors synthesize and characterize a series of atomically defined dithio- and diselenophosphate-protected eight-electron superatomic palladium-doped silver nanoclusters, including an unprecedented pair of selenolate-protected isomers. [ABSTRACT FROM AUTHOR]

Copyright of Precious Metals / Guijinshu is the property of Precious Metals Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Display omitted] The highly selective oxidation of cyclohexane to cyclohexanone and cyclohexanol (KA oil) is one of the most challenging issues in the chemical industry. However, the difficulty in attaining high selectivity and high conversion rate in parallel for the existing catalysts limits its practical application. In this paper, a novel photo-thermo synergistic catalyst was reported for the aerobic oxidation of cyclohexane. The uniform blue MoO 3-x nanowires with small diameter stabilized by polyvinyl pyrrolidone (PVP) were synthesized by a hydrothermal method, and a series of MoO 3-x -AgPd composite materials of different proportions were prepared by an in-situ reduction process. The morphology, crystalline structure, surface chemical bonding, photoelectrochemical properties of MoO 3-x -AgPd composites are thoroughly characterized. The MoO 3-x -AgPd composites present significantly increased catalytic performance than MoO 3-x nanowires in the photo-thermo synergistic catalytic oxidation of cyclohexane under dry air. The high conversion rate of 11.3% with the KA oil selectivity of 99.0% was achieved by the MoO 3-x -Ag 20 Pd 20 composites under photo-thermo catalytic process at 120 ℃, which is 1.5 times of that by MoO 3-x nanowires. Under photo-thermo catalytic process, a high cyclohexane conversion rate similar to that of higher temperature thermal catalysis can be obtained at lower reaction temperature, and more cyclohexanol can be produced with a ketone to alcohol (K/A) ratio of 0.254. The significantly enhanced catalytic activity can be attributed to the effective charge transfer in the AgPd alloy nanoparticles, the optimized band gap structure, the suppressed charge recombination, and the promoted photo-thermo synergetic catalytic effect. This work provides a new reference scheme for the design and preparation of high-efficiency photo-thermo catalysts for the selective oxidation of cyclohexane. [ABSTRACT FROM AUTHOR]

The field of electrochemical CO2 reduction has been transitioning to industrially relevant scales by changing the architecture of the electrochemical cells and moving away from the traditional aqueous H‐cells to membrane electrode assemblies (MEA). The reaction environments in MEAs vary drastically from that of aqueous H‐cells, which could result in significantly different catalytic activity. In this paper, we test AgPd alloys, one of the most promising CO producing catalysts reported, at industrially relevant scales (50 to 200 mA/cm2) in a MEA configuration. We report that, with increasing Pd composition in the electrode, the CO selectivity reduces from 99 % for pure Ag to 73 % for pure Pd at 50 mA/cm2. The MEA configuration helps attain a high CO partial current density of 123 mA/cm2. We find that catalytic activity reported in aqueous H‐Cells does not translate at higher current densities and that cell architecture must play an important role in benchmarking catalytic activity. [ABSTRACT FROM AUTHOR]

Copyright of Eastern-European Journal of Enterprise Technologies is the property of PC TECHNOLOGY CENTER and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ion migration and corrosion behavior in Ag-4Pd alloy wires with fine and coarse grains in the outer regions were evaluated with water drop tests. The results from the in situ observations and measurements of Ag ion migration in both Ag-4Pd bonding wires indicated that the fine-grained wire had much shorter times of dendrite contact and short circuit than those of coarse-grained wire for various wire spaces. It was obvious that grain refinement in Ag-4Pd alloy wires accelerated the ion migration of Ag-4Pd alloy wires. Electrochemical polarization tests confirmed that the passive film on fine-grained Ag-4Pd wire was easily broken down, leading to a higher Ag dissolution tendency than that of coarse-grained wire. Although an annealing twin-rich Ag-4Pd alloy wire was shown to enhance the thermal stability of the grain structure and mechanical properties, the large number of twins had no influence on the formation of Ag dendrites on the cathode and Ag2O oxide on the anode of the coarse-grained Ag-4Pd wire couple during ion migration. [ABSTRACT FROM AUTHOR]

Pd-Ag alloys are largely used as hydrogen separation membranes and, as a consequence, the Pd-Ag-H system has been intensively studied. On the contrary, fewer information is available for the Pd-Ag-D system; thus, the aim of this work is to improve the knowledge of the isotope effect on the commercial Pd77Ag23 alloy, especially for temperature above 200 °C. In particular, deuteriumabsorption measurements are carried out in the Pd77Ag23 alloy in the temperature range between 79 and 400 °C and in the pressure range between 10􀀀2 and 16 bar. In this exploited pressure (p) and composition (c) range, above 300 °C the pc isotherms display the typical shape of materials where only a solid solution of deuterium is present while at lower temperatures these curves seem to be better described by the coexistence of a solid solution and a deuteride in a large composition range. The obtained results are compared and discussed with the ones previously measured with the lightest hydrogen isotope. Such a comparison shows that the Pd77Ag23 alloy exhibits a clear inverse isotope effect, as the equilibrium pressure of the Pd-Ag-D system is higher than in Pd-Ag-H by a factor of ≈2 and the solubility of deuterium is about one half of that of hydrogen. In addition, the absorption measurements were used to assess the deuteration enthalpy that below 300 °C is ΔHdeut = 31.9 ± 0.3 kJ/mol, while for temperatures higher than 300 °C, ÄHdeut increases to 43 ± 1 kJ/mol. Additionally, in this case a comparison with the lighter isotope is given and both deuteration enthalpy values result lower than those reported for hydrogenation. The results described in this paper are of practical interest for applications operating above 200 °C, such as membranes or packing column, in which Pd77Ag23 has to interact with a gas stream containing both hydrogen isotopes. [ABSTRACT FROM AUTHOR]

Acting by producing reactive oxygen species (ROS) in situ, nanozymes are promising as antimicrobials. ROS' intrinsic inability to distinguish bacteria from mammalian cells, however, deprives nanozymes of the selectivity necessary for an ideal antimicrobial. Here we report that nanozymes that generate surface-bound ROS selectively kill bacteria over mammalian cells. This result is robust across three distinct nanozymes that universally generate surface-bound ROS, with an oxidase-like silver-palladium bimetallic alloy nanocage, AgPd0.38, being the lead model. The selectivity is attributable to both the surface-bound nature of ROS these nanozymes generate and an unexpected antidote role of endocytosis. Though surface-bound, the ROS on AgPd0.38 efficiently eliminated antibiotic-resistant bacteria and effectively delayed the onset of bacterial resistance emergence. When used as coating additives, AgPd0.38 enabled an inert substrate to inhibit biofilm formation and suppress infection-related immune responses in mouse models. This work opens an avenue toward biocompatible nanozymes and may have implication in our fight against antimicrobial resistance. Nanozymes have been used for antibacterial applications but have potential toxicity to mammalian cells. Here the authors suggest that nanozymes that generate surface bound reactive oxygen species disrupt bacterial cell walls but not mammalian cells walls due to the different particle uptake mechanisms. [ABSTRACT FROM AUTHOR]

Silver (Ag), palladium (Pd), and bimetallic silver-palladium (Ag-Pd) coatings were deposited on a mild steel surface by the co-sputtering method. The aim was to investigate and compare the corrosion behavior of Ag-Pd nano-coatings as well as the effect of increasing the weight ratio of Ag in the Ag-Pd alloy in the 3.5% NaCl solution. The corrosion protection performance and barrier protection properties were monitored using electrochemical impedance spectroscopy and potentiodynamic polarization. The surface of the coatings was characterized by scanning electron microscopy, atomic force microscopy, energy-dispersive x-ray spectroscopy, and field-emission scanning electron microscopy. The results of corrosion measurements revealed a relationship between silver wt.% and corrosion resistance. Also, all the coatings had protective effects and barrier properties on the mild steel in the corrosive solution. The best efficiency was observed in silver monometallic coating with 54 nm thickness. [ABSTRACT FROM AUTHOR]

Hydrogen, deuterium, and helium gases were separately cycled through a Johnson-Matthey purifier containing coiled palladium silver alloy tubing: Pd25Ag (75 wt% Pd and 25 wt% Ag). During the cycling of D 2 gas, evidence of anomalous heat production was observed. However, during the cycling of H 2 and He, very little (H 2) or no (He) unusual heat events were observed. After cycling the D 2 gas through the coiled tubing for several months, Pd25Ag samples showed an increase in Cu and Fe compared with the amounts in unexposed Pd25Ag. Chromium, manganese, and zinc were detected in gas-cycled Pd25Ag samples, whereas they were not detected in unexposed Pd25Ag samples. In particular, Zn was present in the gas-cycled Pd25Ag material in larger quantities than either Cr or Mn. Although a small amount of Cu was present in the Pd25Ag coil before the D 2 gas cycling, 7 times more was present after the cycling. Multiple material characterization techniques were used to obtain both pre-test and post-test elemental composition. The results indicate that novel post-test elements, primarily on the surface, were created by unknown nuclear mechanisms at low energy. • Surface transmutations occurred in deuterium gas cycling experiments of PdAg tubes. • Zn and Cr not present in PdAg before experiments were observed on PdAg afterwards. [ABSTRACT FROM AUTHOR]

Gas-phase Ag–Pd clusters in the size range of 38–100 atoms are studied via a combined density-functional/empirical-potential (DF-EP) approach. Many-body EPs describing Pd–Pd, Ag–Ag, and Ag–Pd interactions are reparametrized and used in thorough global optimization searches at sizes N=38, 60, and 100 and compositions 25%, 50%, and 75%. The results are analyzed in terms of structural families, whose lowest-energy isomers are reoptimized at the DF level to investigate the crossover among structural motifs. It is found that the reparametrized EPs show a better qualitative and quantitative agreement with DF results when compared to the original potentials taken from literature: Both methods agree on which is the lowest-energy isomer at each size and composition, and the energy differences in the various isomers are in good qualitative agreement, especially for 60- and 100-atom clusters. The reparametrized potentials should thus be applicable to large clusters, where DF calculations are not feasible any more. [ABSTRACT FROM AUTHOR]

• Systematic study of superpermeation in Pd, PdCu, and PdAg foils. • Argon sputter clean enable high and stable superpermeation. • Flux through PdCu 5X greater than Pd∼PdAg, reflecting faster desorption kinetics. • Flux >10−2 mol H m−2 s−1 achieved. • 100% superpermeation of supplied H 2 achieved. Superpermeation of hydrogen isotopes through metal foils is a critical component for efficient fuel recycling in fusion power systems. In that context hydrogen permeation through foils of palladium and its alloys with silver and copper was studied at low temperature (60 - 200°C) under plasma exposure. These alloys differ significantly in both bulk and surface properties, and comparisons can provide mechanistic insights. Permeation was observed only during plasma operation, confirming the negligible contribution of molecular hydrogen to the observed flux. As-received foils required surface treatment to achieve top performance. For Pd and Pd75Ag25 an oxidation treatment increased permeation an order of magnitude, but proved unstable as this desirable surface was reduced under hydrogen plasma exposure. In contrast, an Ar plasma cleaning step provided both high and stable flux. As-received FCC phase Pd60Cu40 foils required annealing to transform it into the high permeability BCC phase that delivered top performance. All foils displayed similar temperature dependence with flux declining with temperature, suggesting that the primary rate-limiting step is absorption of superthermal hydrogen. Among these foils the hydrogen flux through PdCu was 3 - 5X greater than that of Pd or PdAg, which were similar. The superiority of BCC PdCu is attributed to its superior hydrogen desorption kinetics. Using PdCu 100% permeation of supplied hydrogen was achieved, and the flux saturated with increasing plasma power at values >10−2 mol H·m−2·s−1, and under these conditions permeation rates are equivalent with or without the membrane present. The fluxes achieved are the highest reported to date at these conditions, and the results highlight the important roles of both surface and bulk properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Purpose: A longitudinal 5-year clinical investigation was carried out to compare screw-retained frameworks constructed from two alloys with different mechanical properties, either gold or silver-palladium, supported in the mandible by the Astra Tech implant system. Materials and Methods: Twenty-six edentulous patients with mandibular implants were divided into two groups: group A was provided with Chicago IV gold alloy superstructures, and group B was provided with Palliag M silver-palladium alloy superstructures. The surgical procedures for placing the mandibular bone implants and the prosthodontic and laboratory techniques for constructing the prostheses were carried out according to standard, well-documented practices. All patients wore conventional maxillary complete dentures. The integrity of prostheses and health of supporting tissues were compared over a 5-year period. Results: Both materials had similar accuracy of fit and resistance to functional stress, although silver-palladium was technique sensitive and necessitated meticulous laboratory practice to achieve accuracy of casting. Clinical performance of both prostheses was similar, and radiographic assessment showed no statistically significant differences in periimplant bone changes. Conclusion: There were no differences in clinical performance and radiographic changes between the two materials. Therefore, silver-palladium alloy may be considered a suitable low-cost substitute for gold alloy for fixed implant-supported prostheses. [ABSTRACT FROM AUTHOR]

The paper presents Monte Carlo simulation of the hydrogen absorption in palladium and palladium-silver alloy of the composition PdxAg1-x (x = 0.7-0.9) at 293-373 K temperature and 0.1 MPa pressure. Hydrogen atoms in palladium lattice locate mostly in octahedral holes in a face-centered cubic unit cell. In palladiumsilver alloy with the increased Ag content, the absorption energy distribution of hydrogen becomes wider. The interatomic Ag-H distance is shorter than Pd-H distance that means that when contacting with Ag atoms, H atoms occupy less stable tetrahedral holes. When the amount of silver in the alloy grows up to 30 аt.% H atoms are more likely to locate in tetrahedral vacancies resulting in the stability decrease of the system with hydrogen dissolved in the bulk of the material. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ozone-assisted catalysis was able to remove CO efficiently at room temperature. • Bimetallic Ag-Pd catalyst exhibited a cooperative effect. • In situ FTIR measurement provided useful insights into the mechanism of the catalytic reaction. Abstract The room-temperature oxidation of CO using ozone-assisted catalysis (OAC) over monometallic or bimetallic catalysts supported on γ-Al 2 O 3 is presented. Within the tested particle size range, ozone decomposition was insensitive to the size of the Ag particles (6.6–11.9 nm) at weight hourly space velocities of up to 360 L·g−1·h−1. Among the tested monometallic catalysts (Ag Pd, Fe, Mn, and Cu), Ag showed the highest activity for CO oxidation. Bimetallic catalysts (Ag-M or Pd-M where M = Cu, La, Ru, and Fe) were also considered by adding a second metal or perovskite oxide (LaFeO 3) to Ag. A cooperative effect was observed with the bimetallic Ag-Pd catalyst for the OAC of CO oxidation at room temperature, whereas the other bimetallic catalysts showed slightly lower performance compared to the monometallic catalyst. A high ozone utilization efficiency of 0.94 was achieved with the bimetallic Ag-Pd/γ-Al 2 O 3 catalyst. High-angle annular dark-field scanning tunneling electron microscopy (HAADF) and energy dispersive X-ray (EDX) spectroscopy measurements confirmed the proximity of the two components, which is essential for their interaction. The in situ FTIR measurements revealed that the cooperative effect in the bimetallic Ag-Pd catalyst involved modification of CO adsorption and the suppression of product accumulation. Two typical IR absorption bands of linear- (2090 cm−1) and bridge-CO (1918 cm−1) on Pd disappeared in the presence of Ag nanoparticles. Thus, the presence of Ag in contact with Pd inhibited the accumulation of carbonates, which led to enhanced catalytic performance. Adsorption site-dependent CO oxidation on Pd was also confirmed by the in situ Fourier transform IR measurement. [ABSTRACT FROM AUTHOR]

Highlights • Hydrogen permeation in a PdAg alloy is traced in situ by UHV and ambient XPS. • Spectral variations of the surface Ag atom are observed at the adsorption process. • Pd atoms were found to be reactive sites during hydrogen absorption. • The Pd segregation likely promotes the hydrogen permeation. Abstract The hydrogen permeation process is crucial for hydrogen purification through a metal alloy. At the initial stage, it is connected with the dissociation and adsorption of hydrogen on the surface; subsequently, the process involves hydrogen absorption in the bulk. On the PdAg 23 alloy, we investigated the mechanisms of adsorption and absorption by in-situ ultrahigh vacuum and ambient pressure X-ray photoelectron spectroscopy (AP-XPS) measurements, respectively. During the adsorption under a H 2 pressure of 5 × 10−8 Torr at 300–620 K, the surface Ag atoms act as adsorption sites for the hydrogen atoms. The AP-XPS results show that hydrogen absorption is significantly enhanced above 473 K under H 2 exposure at 1.5 Torr, which is likely correlated to the α - β hydride phase transition occurring around 473 K. Hydrogen preferentially bonds with the Pd atoms rather than the Ag atoms in the case of hydrogen absorption into the PdAg 23 alloy. The atomic fractions of Pd on the surface were enhanced after hydrogen absorption, and hydrogen adsorption at a hydrogen pressure of 5 × 10−8 Torr at 620 K. This surface segregation of Pd atoms provides more reactive sites for hydrogen absorption, which may promote the hydrogen permeability of a PdAg 23 alloy. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ag@Pd core-shell structure catalyst can be synthesized by galvanic replacement. • Electron shift in Ag@Pd structure increases local electron density around Pd atom. • Ag@Pd structure can promote phase transformation from Pd0 to PdO state. • Ag@Pd/TiO 2 exhibits higher methanol oxidation activity with a lower Pd loading. Abstract We show that silver palladium bimetallic core-shell structure catalysts supported on TiO 2 substrate (Ag@Pd/TiO 2) are highly active with a low palladium loading for toluene purification in oxidation reaction. The Ag@Pd catalysts were synthesized by galvanic replacement of Pd coating on Ag nanoparticles. Transmission electron microscopy (TEM), high-resolution TEM, and scanning TEM with energy dispersive spectrometer confirmed that the catalysts have a core-shell configuration, and are spherical in shape with an average diameter size of about 9.0 nm. The UV–vis absorption spectroscopy and selected area electron diffraction further proved that the intimate contact and different electronegativity of Ag and Pd in core-shell structure result in electrons transferring from Ag core to Pd shell, which increases local electron density around Pd atom. In addition, X-ray photoelectron spectroscopy reveals that such an increase of electron density on Pd active site in Ag@Pd/TiO 2 catalyst can substantially strengthen the chemisorption with reactant of O 2 , further promote the phase transformation from Pd0 metal to PdO oxidation state, and finally maintain the normal operation of Pd0-PdO synergic mechanism during toluene oxidation reaction. Hence, compared to monometallic Pd/TiO 2 catalyst, the as-prepared bimetallic core-shell Ag@Pd/TiO 2 catalyst exhibits greatly higher toluene oxidation activity as a whole although its palladium loading value is just one third of Pd/TiO 2. The high catalytic oxidation activity with a low Pd loading makes the Ag@Pd/TiO 2 a promising catalyst for use in VOCs purification. [ABSTRACT FROM AUTHOR]

Abstract: A series of model bimetallic Pd-Ag catalysts with different ratios of metals and size distributions of supported particles was prepared by successive metal deposition onto a modified surface of highly oriented pyrolytic graphite (HOPG). X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) were used to characterize the structural and electronic properties, as well as the morphology of nanoparticles at all stages of catalyst preparation. The use of the method made it possible to obtain bimetallic particles with various structures: alloyed, core-shell, and those consisting of individual monometallic particles. The XPS method with synchrotron radiation was used to determine the patterns in the formation of alloyed bimetallic particles, their chemical composition, structure, and the ranges of thermal stability under conditions of ultrahigh vacuum. [ABSTRACT FROM AUTHOR]

Abstract: The Pd-Ag/CeO2 catalysts were prepared by the impregnation of highly dispersed CeO2 with a solution of the heteroatomic complex PdAg2(OAc)4(HOAc)4. Samples obtained after the thermolysis of PdAg2(OAc)4(HOAc)4 in N2 and H2 contained Pd-Ag alloy and Pd particles immobilized on CeO2. The Pd0-CeO2 metal oxide centers formed at the interface were highly active in the low-temperature reaction of CO oxidation. The particles of Pd were absent from the Pd-Ag/CeO2 sample prepared by the decomposition of PdAg2(OAc)4(HOAc)4 in an atmosphere of O2; in this case, a significant portion of the Pd-Ag phase was covered with a film of CeO2, which dramatically slowed down the rate of reaction at low temperatures. [ABSTRACT FROM AUTHOR]

The failure mechanism of the electromigration in Ag-Pd bonding wires was investigated through stressing with a current density of 1.23 × 105 A/cm2 at temperatures of 150 °C to 300 °C. It was found that the grains of the wire materials grew rapidly during current stressing for 100 minutes at various temperatures. In contrast, the grain structure remained almost unchanged after storage at these temperatures for 100 minutes without current stressing. The mean-time-to-failure (MTF) for various current-stressed Ag-Pd alloy wires decreased with increases in Pd content. The activation energy for the electromigration of these wire materials was measured, and the results indicated that the main driving force was surface diffusion of Ag. [ABSTRACT FROM AUTHOR]

This study investigated the failure mechanism of Ag-4Pd wire bonded on Al metallization under chlorine corrosive environments after high temperature storage tests (HTST) and thermal cycle tests (TCT). Results show that as-bonded samples encountered the fastest failure, caused by corrosion of Al metallization accelerated by galvanic corrosion. For HTST samples, the intermetallic compound (IMC) layer was corroded and separated into the upper layer of Ag 2 Al and Ag 3 Al and the lower layer of Ag 3 Al 2 . The non-continuous Ag 3 Al 2 IMC layers in TCT samples can act as a barrier to inhibit the galvanic corrosion and effectively retard the corrosion rate of Al metallization. [ABSTRACT FROM AUTHOR]

A method for the preparation of mixed AuPd nanoparticles that are used as catalysts for selective alkyne Z‐semihydrogenation is described. It is shown that the corresponding monometallic Pd nanoparticles display a lower activity, documenting the cooperative effect exerted by the two metals. These mixed AuPd nanoalloys are readily prepared by irradiation of the corresponding precursor salts in the presence of photoactive polymers or commercially available photoinitiators as reducing and stabilizing agents. Alkyne semihydrogenation using these catalyst systems with H2 proceeds in high yield (up to 97 % yield of isolated product) and excellent Z‐selectivity (up to 99 %). Hydrogenations work on larger scale and the hybrid catalyst can be recovered and reused by simple centrifugation. [ABSTRACT FROM AUTHOR]

The three-dimensional distortions of implant frameworks of two designs, reflecting the early "Toronto" U-shaped design and a current L-shaped design, were measured. A conventional commercial laboratory one-piece casting method, using a silver-palladium alloy, was used. Distortion was defined by five displacement variables for the centroids of each of five gold cylinders incorporated in each casting: three orthogonal translational displacements (dx, dy, and dz) and two rotational displacements (dϴx and dϴy). A computerized coordinate measuring machine was used. Overall translational displacements measured were -17.4 ± 15 μm for dx, 6.1 ± 7.1 μm for dy, and -0.1 ± 1.7 μm for dz. The overall global translational displacement, dR, was 20.2 ± 14.5 μm. Overall rotational displacements were -0.098 ± 0.109 degrees for dϴx and -0.020 ± 0.097 degrees for dϴy, giving an average absolute angular change, dϴR, of 0.158 ± 0.077 degrees. No significant differences were found between U- and L-shaped castings, except for dy values for cylinders 2, 3, and 4, and dϴx values for cylinder 1. Cylinder location within the arch was associated with a specific direction and magnitude of translational and rotational displacement. Even small rotational displacements may manifest large gap appearances with the one-screw test because of the "moment arm" effect. However, other rotational displacements may be hidden, depending on the direction of tilt and the moment arm length. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the fracture resistance of computer-aided design/computer-assisted manufacture (CAD/CAM)-fabricated fiber-reinforced composite (FRC) denture retainers. Distal extension dentures incorporating two telescopic retainers and two molar pontics, with or without fiberglass, were fabricated by CAD/CAM or by the conventional polymerization method. The dentures were subjected to a vertical load on the second molar pontic until fracture. Within each manufacturing method, embedment of the FRC increased the mean final fracture load, suggesting the reinforcing effect of fiberglass. The polymerized dentures with FRC showed greater mean final fracture load than the CAD/CAM dentures with FRC. [ABSTRACT FROM AUTHOR]

The AgPd alloys were electrodeposited onto Au and glassy carbon disc electrodes from the solution containing 0.001 mol dm-3 PdCl2 + 0.04 mol dm-3 AgCl + 0.1 mol dm-3 HCl + 12 mol dm-3 LiCl under the non-stationary diffusion (quiescent electrolyte) and convective diffusion (ω = 1000 rpm) to the different amounts of charge and at different current densities. Electrodeposited alloy layers were characterized by the anodic linear sweep voltammetry (ALSV), scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The compositions of the AgPd alloys determined by the EDS were almost identical to the theoretically predicted ones, while the compositions obtained by XPS and ALSV analysis were similar to each other, but different from those obtained by EDS. Deviation from the theoretically predicted values (determined by the ratio jL(Pd)/j(Ag)) was more pronounced at lower current densities and lower charges of AgPd alloys electrodeposition, due to the lower current efficiencies for alloys electrodeposition. The ALSV analysis indicated the presence of Ag and Pd, expressed by two ALSV peaks, and in some cases the presence of the additional peak, which was found to correspond to the dissolution of large AgPd crystals, formed at thicker electrodeposits (higher electrodeposition charge), indicating, for the first time, that besides the phase structure, the morphology of alloy electrodeposit could also influence the shape of the ALSV response. In addition to Ag and Pd, the XPS analysis confirmed the presence of AgCl at the surface of samples electrodeposited to low thicknesses (amounts of charge). [ABSTRACT FROM AUTHOR]

Abstract: The development of highly efficient and multifunctional sensors for accurately detecting indoor climate has always remained a challenging task. In this work, an important progress for nanocasting synthesis of ordered mesoporous Ag–ZnO‐loaded graphitic carbon nitride (g‐CN) prepared through template inversion of mesoporous silica, KIT‐6, is presented. The cubic 3D ordered mesoporous Ag–ZnO@g‐CN nanohybrid demonstrates excellent sensitivity, rapid response/recovery (5.1/2 s), excellent reversibility (0.3%), high stability, and negligible hysteresis (0.5%) to relative humidity (%RH) in the 11–98%RH range. Besides, it shows outstanding selective response (R = Ra/Rg) of 62.4 and 37.6 under dry and 90%RH environment, respectively, along with a fast response/recovery (16.1/10.5 s) time toward detection of acetone at 200 °C. In addition, the sensor shows excellent response at significant lower operating temperatures (R = 3.2 at 60 °C and R = 6.7 at 80 °C) to 50 ppm acetone gas. Compared to mesoporous Ag–ZnO, the g‐CN supported Ag–ZnO nanocomposite shows ≈1.8 times better response to acetone while marking an impressive reduction in optimized operating temperature by 50 °C. The findings in this study add insight and assist in the further optimization of this new class of 2D layered ordered mesoporous materials in realizing next‐generation sensors with multiple utilities. [ABSTRACT FROM AUTHOR]

Abstract: Exceedingly chemoselective preparation of secondary amines from the cascade reaction of nitro reduction followed by reductive amination of the resulting amine with an aldehyde through the use of bimetallic AuPd alloy nanoparticle catalyst is described. We prepared a AuPd alloy nanocatalyst supported on Fe3O4 in gram scale without calcination. One pot synthesis of a number of secondary amines was achieved from a variety of nitroarenes and aryl or alkyl aldehydes under 1 atm of H2 at room temperature. No N‐debenzylation was observed in the case of the reactions involving aryl aldehydes, which is often observed in the reductive amination catalysed by a transition metal catalyst such as palladium. We also accomplished efficient one‐pot synthesis of a number of N‐aryl substituted isoindolinone derivatives from 1‐formylbenzoic acid and several nitroarenes using the same reaction conditions. Furthermore, thanks to the magnetic property of the Fe3O4 support, the AuPd−Fe3O4 NPs could be easily separated and reused up to 20 times without the loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

One-dimensional bimetallic Pd@Au core-shell nanorods (NRs) with uniform Au shell were synthesized and applied to construct a highly sensitive acetylcholinesterase (AChE) biosensor for the detection of organophosphate pesticides (OPs). The Pd@Au core-shell nanorods with excellent conductivity, pure contact surface and good biocompatibility can provide an extremely suitable area for the adhesion of AChE. Due to these characteristics, the constructed sensor exhibits a superior performance. The biosensor was prepared via a simple procedure and its optimization studies were discussed. Under optimal conditions, the inhibition of paraoxon (as a model compound for OPs) in linearly proportional to its concentration in the range of 3.6 pM–100 nM, with the detection limit of 3.6 pM (calculated for 10% inhibition). The KMapp value of the fabricated enzyme electrode was calculated to be 0.207 mM. The application of this biosensor in the analysis of real samples was also evaluated. Moreover, the prepared biosensor possessed higher sensitivity and acceptable reproducibility and stability, showing great potential in the detection of OPs. [ABSTRACT FROM AUTHOR]

AgPd alloy nanoparticles (NPs) supported on halloysite nanotubes (HNTs) coated polydopamine (PDA) successfully synthesized by one-pot hydrothermal route. XRD, TEM and XPS were employed to verify the alloy structure of the obtained AgPd NPs. The HAADF-STEM result revealed that the thickness of PDA coating was ∼10 nm, which could be formed on the surface of HNTs, and the existence of PDA was beneficial to deposit AgPd alloys with high dispersibility on the surface of HNTs. AgPd/PDA-HNT nanocomposites were effective catalysts for the hydrolysis of ammonia borane at room temperature, and the reaction was completed within 160 s using Ag 3 Pd 2 /PDA-HNT as catalysts, with a high total turnover frequency (TOF) value of 90 mol H2 mol catalyst −1 min −1 and a low apparent activation energy (Ea) of 22.7 kJ mol −1 . After the sixth cycle, Ag 3 Pd 2 /PDA-HNT catalyst retained 72% of its initial activity and 100% conversion. The excellent catalytic properties, good durability and reusability, enabled Ag 3 Pd 2 /PDA-HNT to be an ideal catalyst in the practical applications. [ABSTRACT FROM AUTHOR]

The paper deals with hydrogen transfer through Pd-23%Ag alloy membrane, the surface of which is modified by the electrolytic deposition of highly dispersed palladium. The dependence between the density of hydrogen flow and its excess pressure on the input surface of membrane is well approximated by the first-order curve. This fact indicates that the process of hydrogen permeability is defined by its dissociation on the input surface. Activation energy of this process is 47.9 kJ/mol which considerably exceeds that of the process of hydrogen transfer through palladium (22-30 kJ/mol). This confirms the fact that the chemisorption is a rate-controlling step of the hydrogen transfer through membrane. [ABSTRACT FROM AUTHOR]

Biosynthesis of silver and palladium nanoparticles was carried out by using Lithodora hispidula (Sm.) Griseb. Leaf extract as a reducing agent. The silver and palladium nanoparticles (NPs) were characterized by UV-Visible spectroscopy, inductively coupled Plasma-Mass Spectrometer, X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis. UV-Vis spectra of biosynthesized silver nanoparticles showed an absorption band at 425 nm. The formation of palladium nanoparticles was confirmed by the disappeared absorption band at 410 nm. Scanning electron microscopy analysis showed that Ag, AgPd spherical and Pd nanoparticle morphology were rod in shape. The electrochemical behaviour of Ag, Pd and AgPd alloy nanoparticles were investigated by cyclic voltammetry. Modified glassy carbon electrodes were constructed by using Ag, Pd and AgPd nanoparticles and used in electrocatalytic reduction of hydrogen peroxide in phosphate buffer medium (pH = 6.5), in potential range of 0.0 and -0.8 V vs . Ag/AgCl at 100 mV/s scan rate. The AgPdNPs-GCE based sensor could detect the H 2 O 2 in the linear range of 0.02–5.0 mM with a detection limit of 0.52 μM. The AgPdNPs-GCE showed a good repeatability and stability for detection of H 2 O 2 . Furthermore, it exhibited no interference with some biological species such as glucose, ascorbic acid and uric acid. [ABSTRACT FROM AUTHOR]

Silver–palladium (Ag–Pd) alloy nanoparticles strongly absorb visible light and exhibit significantly higher photocatalytic activity compared to both pure palladium (Pd) and silver (Ag) nanoparticles. Photocatalysts of Ag–Pd alloy nanoparticles on ZrO2 and Al2O3 supports are developed to catalyze the nitroaromatic coupling to the corresponding azo compounds under visible light irradiation. Ag–Pd alloy NP/ZrO2 exhibited the highest photocatalytic activity for nitrobenzene coupling to azobenzene (yield of ∼80% in 3 hours). The photocatalytic efficiency could be optimized by altering the Ag : Pd ratio of the alloy nanoparticles, irradiation light intensity, temperature and wavelength. The rate of the reaction depends on the population and energy of the excited electrons, which can be improved by increasing the light intensity or by using a shorter wavelength. The knowledge developed in this study may inspire further studies on Ag alloy photocatalysts and organic syntheses using Ag–Pd nanoparticle catalysts driven under visible light Irradiation. [ABSTRACT FROM AUTHOR]

A conformationally flexible template for the meta-C-H olefination of benzoic acids was designed through both experimental and computational efforts. The newly designed template favors a silver-palladium heterodimer low barrier transition state, and demonstrates that it is feasible to lengthen templates so as to achieve meta-selectivity when the distance between the functional handle of the native substrate and target C-H bond decreases. Analysis of the ortho-, meta-, and para-C-H cleavage transition states determined that the new template conformation optimizes the interaction between the nitrile and palladium-silver dimer in the meta-transition state, enabling palladium to cleave meta-C-H bonds with moderate-to-good yields and generally high regioselectivity. Regioselectivity is governed exclusively by the template, and kinetic experiments reveal that there is a 4-fold increase in rate in the presence of monoprotected amino acid ligands. Using a Boltzmann distribution of all accessible C-H activation transition states, it is possible to computationally predict meta-selectivity in a number of investigated templates with reasonable accuracy. Structural and distortion energies reported may be used for the further development of templates for meta-C-H activation of hitherto unexplored arene substrates. [ABSTRACT FROM AUTHOR]

This paper demonstrates femtosecond laser direct writing mediated flexible integration of plasmonic Ag/Pd alloy nanostructures that can be potentially used as a robust surface‐enhanced Raman spectroscopy substrate inside the microfluidic chip. Silver–palladium alloy with controllable composition ratio can be patterned into plasmonic nanostructures due to two‐photon absorption induced coreduction of silver/palladium double metal ions. Since the alloy structures can effectively protect the silver from oxidation, thus they can facilitate the stable on‐chip detection devices with long lifetime. The as‐fabricated silver–palladium alloy substrate with 18% content of palladium maintains a relatively high enhancement factor of about 2.62 × 108 while at the same time demonstrating the best stability against aerobic oxidation, as it is stable for up to 20 d under ambient aerobic conditions, exhibiting a significant improvement compared to those unprotected silver substrates which have a limited lifetime of only 3 or 4 d. [ABSTRACT FROM AUTHOR]

Carbon dioxide is the primary greenhouse gas and its emission has caused serious problems with respect to climate change. Unremitting efforts are being made to recycle of CO2 through its hydrogenation to liquid fuels such as CH3OH. Pd-ZnO based nanoarchitectures are one type of ideal catalysts for CO2 hydrogenation. However, owing to the lack of palladium reserves, enhancing the catalytic efficiency and selectivity of the palladium nanostructures so that low loadings can be used remains a scientific challenge. Three types of ZnO-supported Ag@Pd core@shell, AgPd alloy, and pure Pd nanocatalysts were controllably and successfully synthesized. Benefiting from the electron-rich Pd shell and the formation of the PdZn phase in the Ag@Pd-ZnO core@shell structure, we achieved a catalytic efficiency per gram of palladium that is 3.32 times higher than the Pd-ZnO nanostructure. In particular, electron transfer at the interfaces and the adsorption of the intermediate species significantly enhance catalytic selectivity of the Ag@Pd-ZnO core@shell structure. This work proposes a novel strategy to enhance the methanol yield during CO2 hydrogenation by the sophisticated tailoring of the surface composition in noble-metal catalysts. [ABSTRACT FROM AUTHOR]

We introduce the class of discrete silver(I)-palladium(II)-oxo nanoclusters with the preparation of {Ag4Pd13} and {Ag5Pd15}. Both polyanions represent the first examples of noble metal-capped polyoxo-noble-metalates in a fully inorganic assembly, featuring an unprecedented host-guest mode containing hetero- and homometallic Ag-Pd and Ag-Ag bonding interactions. Comprehensive theoretical calculations suggest that the Ag-Pd metallic bonds originate partially from surface confinement of AgI guest ions onto the anionic polyoxopalladate host that is induced by strong electrostatic forces. This work opens the field of fully inorganic silver-palladium-oxo nanoclusters, which can be considered as discrete mixed noble metal precursors for the formation of monodisperse core-shell nanoparticles, with high relevance for catalysis. [ABSTRACT FROM AUTHOR]

Radioactive iodine is the Achilles' heel in the design for the safe geological disposal of spent uranium oxide (UO 2 ) nuclear fuel. Furthermore, iodine's high volatility and aqueous solubility were mainly responsible for the high early doses released during the accident at Fukushima Daiichi in 2011. Studies Kienzler et al., however, have indicated that the instant release fraction (IRF) of radioiodine ( 131/129 I) does not correlate directly with increasing fuel burn-up. In fact, there is a peak in the release of iodine at around 50–60 MW d/kgU, and with increasing burn-up, the IRF of 131/129 I decreases. The reasons for this decrease have not fully been understood. We have performed microscopic analysis of chemically processed high burn-up UO 2 fuel (80 MW d/kgU) and have found recalcitrant nano-particles containing, Pd, Ag, I, and Br, possibly consistent with a high pressure phase of silver iodide in the undissolved residue. It is likely that increased levels of Ag and Pd from 239 Pu fission in high burnup fuels leads to the formation of these metal halides. The occurrence of these phases in UO 2 nuclear fuels may reduce the impact of long-lived 129 I on the repository performance assessment calculations. [ABSTRACT FROM AUTHOR]

Silver-palladium alloy wire has been shown as an economical and reliable substitute for gold wire in various applications in the electronic packaging industry. The success of wire bonding relies on the formation of an interfacial intermetallic compound (IMC). This study is aimed to investigate the formation behavior of IMCs between an Al pad and Ag-Pd alloy wire with various Pd concentrations of 1.0-6.0% for the as-bonded commercial Ag/Al joint. The interfacial IMCs were investigated with scanning electron microscopy and energy-dispersive x-ray spectroscopy. The IMCs formed are separate (Ag, Pd)Al and (Ag, Pd)Al for a Ag6Pd wire bond, while (Ag, Pd)Al and (Ag, Pd)Al are mixed for the other Ag(1-4.5)Pd alloy wire bonds. The thickness of the total IMC layer varies from 0.65 μm for Ag1Pd to 0.91 μm for Ag6Pd, yet a minimum of 0.44 μm exists for Ag3.5Pd. The compound formation behavior was found to correspond with the Ag-Al phase diagram. After pressure cooker tests, a less stable IMC (Ag, Pd)Al formed at the AgxPd/Al interface. [ABSTRACT FROM AUTHOR]

Mathematical models of degradation-relaxation kinetics are considered for jammed thick-film systems composed of screen-printed spinel CuNiCoMnO and conductive Ag or Ag-Pd alloys. Structurally intrinsic nanoinhomogeneous ceramics due to Ag and Ag-Pd diffusing agents embedded in a spinel phase environment are shown to define governing kinetics of thermally induced degradation under 170 °C obeying an obvious non-exponential behavior in a negative relative resistance drift. The characteristic stretched-to-compressed exponential crossover is detected for degradation-relaxation kinetics in thick-film systems with conductive contacts made of Ag-Pd and Ag alloys. Under essential migration of a conductive phase, Ag penetrates thick-film spinel ceramics via a considerable two-step diffusing process. [ABSTRACT FROM AUTHOR]

In this study, galvanic replacement provides a simple route for the synthesis of PdAg hollow nanoflower structures by using the Ag-seeds as sacrificial templates in the presence of l-ascorbic acid (reductant) and CTAC (capping agent). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and EDS mapping were used to characterize the as-prepared PdAg hollow nanoflower catalysts, where they were alloyed nanoflower structures with hollow interiors. By maneuvering the Pd/Ag ratio, we found that the as-prepared Pd1Ag3 hollow nanoflower catalysts had the optimized performance for catalytic activity toward ethanol oxidation reaction. Moreover, these as-prepared PdAg hollow nanoflower catalysts exhibited noticeably higher electrocatalytic activity as compared to pure Pd and commercial Pd/C catalysts due to the alloyed Ag-Pd composition as well as the hollow nanoflower structures. It is anticipated that this work provides a rational design of other architecturally controlled bimetallic nanocrystals for application in fuel cells. [ABSTRACT FROM AUTHOR]

This paper presents the results of the experimental investigation of the generation of nanosecond photocurrent pulses in silver-palladium (Ag/Pd) resistive films under excitation by laser pulses with a duration of 120 fs at a wavelength of 795 nm. The photocurrent was detected in the direction perpendicular to the plane of incidence of the laser beam on the film. The 20-μm-thick films under investigation were a porous polycrystalline material consisting predominantly of nanocrystallites of the palladium oxide PdO and the Ag-Pd solid solution. The direction of the photocurrent observed in the films depends on the sign of the circular polarization of the incident radiation. It was found that the observed photocurrent depends on the angle of incidence in accordance with the odd law and consists of the circular and linear contributions, which are dependent on and independent of the sign of the circular polarization, respectively. It was shown that the circular photocurrent is significantly higher than the linear photocurrent. It was established that, for both the circular and linear polarizations, the photocurrent is directly proportional to the power of the excitation radiation. For the linearly polarized laser radiation, the photocurrent depends on the polarization angle in accordance with the odd law. The regularities revealed are consistent with the mechanism of the generation of transverse photocurrent with the photon drag effect. [ABSTRACT FROM AUTHOR]

In this study, we report the direct synthesis of amides and ureas via the catalytic dehydrogenation of volatile alcohols and amines using the Milstein catalyst in a Pd-Ag/ceramic membrane reactor. A series of amides and ureas, which could not be synthesized in an open system by catalytic dehydrogenation coupling, were obtained in moderate to high yields via catalytic dehydrogenation of volatile alcohols and amines. This process could be monitored by the hydrogen produced. Compared to the traditional method of condensation, this catalytic system avoids the stoichiometric pre-activation or in situ activation of reagents, and is a much cleaner process with high atom economy. This methodology, only possible by employing the Pd-Ag/ceramic membrane reactor, not only provides a new environmentally benign synthetic approach of amides and ureas, but is also a potential method for hydrogen storage. [ABSTRACT FROM AUTHOR]