Pd-Ag Alloy Research Articles

High Efficiency for Methanol Electrooxidation of Self-Supporting 3D Nanoporous PdAg Alloy Foams

The self-supporting three-dimensional (3D) nanoporous PdAg alloy (NP–PdAg) foams have been prepared by a simple one-step dealloying melt-spun Al–Pd–Ag ribbons in a 20[Formula: see text]wt.% NaOH aqueous solution at 90∘C for 1.5[Formula: see text]h. The structure is advantageous to the diffusion and removal of the intermediate products and the transmission of the methanol molecules. The NP–PdAg foams exhibit better electrocatalytic performance than the NP-Pd foam toward the methanol oxidation in potassium hydroxide (KOH) solution. The optimal atomic ratio of Pd to Ag in the NP–PdAg foams is 1:1, and its electrocatalytic activity is about 2.6 times that of the NP–Pd foam. The significant improvement in the electrocatalytic performance is attributed to the addition of a moderate amount of Ag. In the whole electrocatalytic process, Ag can provide OHads to oxidize the intermediate products on the surface of active Pd sites into carbon dioxide or other cleaning products. Also, the Ag can increase electrochemical active surface area and the adsorption energy of Pd to methanol molecules and OHads. These significantly prevent the accumulation of poisoning intermediates on the surface of Pd and quickly release more active Pd sites.

Assessment of Sieverts Law Assumptions and 'n' Values in Palladium Membranes: Experimental and Theoretical Analyses.

Palladium and palladium alloy membranes are superior materials for hydrogen purification, removal, or reaction processes. Sieverts’ Law suggests that the flux of hydrogen through such membranes is proportional to the difference between the feed and permeate side partial pressures, each raised to the 0.5 power (n = 0.5). Sieverts’ Law is widely applied in analyzing the steady state hydrogen permeation through Pd-based membranes, even in some cases where the assumptions made in deriving Sieverts’ Law do not apply. Often permeation data are fit to the model allowing the pressure exponent (n) to vary. This study experimentally assessed the validity of Sieverts’ Law as hydrogen was separated from other gases and theoretically modelled the effects of pressure and temperature on the assumptions and hence the accuracy of the 0.5-power law even with pure hydrogen feed. Hydrogen fluxes through Pd and Pd-Ag alloy foils from feed mixtures (5–83% helium in hydrogen; 473–573 K; with and without a sweep gas) were measured to study the effect of concentration polarization (CP) on hydrogen permeance and the applicability of Sieverts’ Law under such conditions. Concentration polarization was found to dominate hydrogen transport under some experimental conditions, particularly when feed concentrations of hydrogen were low. All mixture feed experiments showed deviation from Sieverts’ Law. For example, the hydrogen flux through Pd foil was found to be proportional to the partial pressure difference (n ≈ 1) rather than being proportional to the difference in the square root of the partial pressures (n = 0.5), as suggested by Sieverts’ Law, indicating the high degree of concentration polarization. A theoretical model accounting for Langmuir adsorption with temperature dependent adsorption equilibrium coefficient was made and used to assess the effect of varying feed pressure from 1–136 atm at fixed temperature, and of varying temperature from 298 to 1273 K at fixed pressure. Adsorption effects, which dominate at high pressure and at low temperature, result in pressure exponents (n) values less than 0.5. With better understanding of the transport steps, a qualitative analysis of literature (n) values of 0.5, 0.5 < n < 1, and n > 1, was conducted suggesting the role of each condition or step on the hydrogen transport based on the empirically fit exponent value.

Bayesian Optimization of High-Entropy Alloy Compositions for Electrocatalytic Oxygen Reduction*.

Active, selective and stable catalysts are imperative for sustainable energy conversion, and engineering materials with such properties are highly desired. High‐entropy alloys (HEAs) offer a vast compositional space for tuning such properties. Too vast, however, to traverse without the proper tools. Here, we report the use of Bayesian optimization on a model based on density functional theory (DFT) to predict the most active compositions for the electrochemical oxygen reduction reaction (ORR) with the least possible number of sampled compositions for the two HEAs Ag‐Ir‐Pd‐Pt‐Ru and Ir‐Pd‐Pt‐Rh‐Ru. The discovered optima are then scrutinized with DFT and subjected to experimental validation where optimal catalytic activities are verified for Ag–Pd, Ir–Pt, and Pd–Ru binary alloys. This study offers insight into the number of experiments needed for optimizing the vast compositional space of multimetallic alloys which has been determined to be on the order of 50 for ORR on these HEAs.

Photo-thermo catalytic selective oxidation of cyclohexane by In-situ prepared nonstoichiometric Molybdenum oxide and Silver-palladium alloy composite

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 MoO3-x nanowires with small diameter stabilized by polyvinyl pyrrolidone (PVP) were synthesized by a hydrothermal method, and a series of MoO3-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 MoO3-x-AgPd composites are thoroughly characterized. The MoO3-x-AgPd composites present significantly increased catalytic performance than MoO3-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 MoO3-x-Ag20Pd20 composites under photo-thermo catalytic process at 120 ℃, which is 1.5 times of that by MoO3-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.

Promising Isotope Effect in Pd77Ag23 for Hydrogen Separation

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, deuterium absorption 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, ΔHdeut 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.

Impact of graphitic carbon nitrides synthesized from different precursors on Schottky junction characteristics.

Graphitic carbon nitride (g-CN) has gained wide interest in many areas, such as energy and the environmental remediation as a layered polymeric semiconductor that allows the formation of catalytically active Schottky junctions due to its proper electronic band structure. Interestingly, although it is known that the precursors used in the synthesis, can influence the properties of the g-CN, no detailed study on these effects on Schottky junctions could be found in the literature. In this research, the effects of g-CNs synthesized by thermal polycondensation of different precursors on the photocatalytic efficiency of Schottky junctions were investigated. For this purpose, urea, thiourea, melamine, and guanidine hydrochloride were used as different precursors, while the photocatalytic dehydrogenation of formic acid was used as a test reaction. The Schottky junctions were formed by decorating the as-prepared g-CNs with AgPd alloy nanoparticles (NP), which were synthesized by reduction of Ag and Pd salts with NaBH4. The structural, electronic and charge carrier dynamics of all prepared structures have been fully characterized by TEM, XRD, BET, XPS, UV-Vis DRS, PL, and PL life measurements. The results showed that the charge transfer dynamics of g-CNs surface defects are more effective in the photocatalytic performance of Schottky junctions than in structural features such as the size of the metal NPs or the surface area of the catalysts.

Co-tuning composition and channel-rich structure of Ag-Pd alloys toward sensitive electrochemical biosensing

Noble-metal nanostructures are promising for biosensing applications owing to their fantastic physicochemical properties, but the rational design of their easy-accessible and reactive surface is still challenging. This work is devoted to the interfacial engineering of Ag-Pd alloys, including tuning alloy composition and geometric structure, to promote the electrochemical biosensing performance. Through a co-tuning tactic with controlled reduction, channel-rich Ag1Pd3 alloys with optimal electronic configurations and accessible active surface are successfully obtained, which afford high sensitivity, outstanding selectivity and excellent repeatability to detect H2O2 and glucose biomarkers. As experimentally and theoretically evidenced, tailoring the composition of Ag-Pd alloys ameliorates electronic configurations due to ligand effects, which can optimize the binding with the key intermediate of OH*, and thereby boost electrochemical kinetic steps on surface. Meanwhile, tuning geometric structure with abundant channels enables fast transport of analytes toward largely-exposed active sites. Providing an atomic-level interpretation of structure-dependent biosensing, this work is anticipated to offer guidelines for the development of efficient sensing platforms.

Pairwise Stereoselective Hydrogenation of Propyne on Supported Pd–Ag Catalysts Investigated by Parahydrogen-Induced Polarization

Alkyne semihydrogenation offers a key approach for the synthesis of stereodefined molecules. The stereoselective hydrogenation of propyne to propene over Al2O3-supported Pd–Ag bimetallic catalysts is studied by using parahydrogen-induced polarization (PHIP) NMR technique. The supported catalysts were prepared by an incipient-wetness impregnation method, and their properties were systemically tuned by altering Pd and Ag components. Structural characterization by X-ray diffraction, infrared spectra, and transmission electron microscope shows the formation of highly dispersed bimetallic Pd–Ag nanoparticles with random alloy structures on Al2O3 support. For the hydrogenation of propyne over Pd–Ag catalysts with higher Ag concentration, the adsorbed protons are mostly restricted on the active Pd ensembles, which favors a higher pairwise hydrogen addition to propyne, leading to a stronger PHIP effect. The product stereoselectivity measurements show that the pairwise syn-addition to propyne increases with Ag content in the Pd–Ag alloy. The reaction conditions impact the pairwise hydrogenation stereoselectivity. A lower H2/propyne ratio of reactant flow or a higher total reactant flow rate enhances the apparent pairwise syn-addition stereoselectivity, which can be accounted for by the suppressed cis–trans isomerization process and/or a higher intrinsic pairwise syn-addition selectivity.

On the Localized Surface Plasmonic Resonances of AgPd Alloy Nanoparticles by Experiment and Theory

Ag/Pd multilayers and AgPd alloyed ultrathin films were deposited on Corning glass by magnetron sputtering. After being annealed in a furnace in air at 460 °C, self-assembled nanoparticles were formed. Localized surface plasmon resonances were observed only for the Ag-rich samples in the full range of the visible light spectrum. The resonance position was found to depend on the initial film thickness. In order to gain further physical insight, rigorous theoretical calculations were carried out via the rigid coupled-wave analysis method for the entire compositional range between Ag and Pd. Theoretical calculations were proven to be in suitable agreement with the experimental results.

N-containing silane coupling agent-assisted synthesis of highly dispersed and stable PdC phase for semi-hydrogenation of acetylene

A highly dispersed and stable PdC phase supported on α-Al2O3 for semi-hydrogenation of acetylene was prepared using N-containing silane coupling agent as a modifier. The catalyst exhibited as much as 15% higher ethylene selectivity than traditional PdAg alloy with full acetylene conversion under 240 °C and performed longer stability within 200 h tolerance test. Characterization results reveal that the excellent ethylene selectivity is mainly derived from the special PdC phase nanoparticle structure with lattice relaxation and distortion. This unique structure makes the catalyst perform weaker adsorption of ethylene, have more abundant spillover hydrogen on the carrier surface and lead a strong interaction between the Pd nanoparticles and surface. Experimental results and DFT calculations have shown the PdC phase is a more promising structure than the commonly used PdAg alloy.

Partial or complete suppression of hysteresis in hydride formation in binary alloys of Pd with other metals

At temperatures below 600 K, the isotherms of hydrogen absorption by Pd exhibit hysteresis loops related to the first-order phase transition or, more specifically, to separation of a diluted phase and hydride. According to the experiments, addition of even small amount of the second metal, e.g. Au or Ta, can appreciably suppress hysteresis. This interesting effect is important in various applications, e.g., in the context of fabrication of efficient hydrogen sensors. To clarify its physical background, we present statistical calculations of the hydrogen absorption isotherms for a series of binary alloys of Pd with Mg, Cu, Ag, Ta, Pt, or Au by using the values of the H-metal interaction provided by the density functional theory (DFT). Aiming at the situations with small amount (≤15%) of the second metal, the metal atoms in an alloy are considered to be located at random or with short-range correlations. In the random alloy approximation, appreciable suppression of hysteresis is predicted for all the additives under consideration except Cu. Concerning the correlations, we show that the tendency of metals to mixing (as, e.g., predicted for the Pd–Au or Pd–Ta alloy) is in favour of additional suppression of hysteresis whereas the tendency to segregation (as, e.g., predicted for the Pd-Ag alloy) makes the hysteresis loops wider. For Au and Ta, our findings are in good agreement with available experimental data.

Porous PdAg alloy nanostructures with a concave surface for efficient electrocatalytic methanol oxidation

Tuning the composition and surface structure of the metal nanocrystals offered viable avenues for enhancing catalytic performances. Herein, we report a facile one-pot strategy for the formation of PdAg porous alloy nanostructures (PANs) with a concave surface. Due to their highly open nanostructures and tunable d-band center features, PdAg PANs exhibit superior electrocatalytic activity and long-term durability than Pd nanoparticles (NPs) and Pd/C for methanol oxidation reaction (MOR) in alkaline media. Our results provide a feasible and efficient approach for the controlled synthesis of high-performance Pd-based nanomaterials for alkaline MOR.

Surface segregation of PdM (M=Cu, Ag, Au) alloys and its implication to acetylene hydrogenation, DFT-based Monte Carlo simulations

The surface composition and atomic arrangement of heterogeneous catalysts determine the surface chemistry and are necessary information for understanding surface catalytic reactions. Compared with monometallic catalysts, alloy catalysts are more complicated because of possible surface segregation or adsorption-induced segregation which may change under different reaction atmosphere. Construction of reasonable slab models to study reactions on alloy surfaces is of importance. Here we proposed a density functional theory based Monte Carlo method (DFT-MC) and used it to investigate the surface composition and atomic arrangement of the (111) surfaces of 1:1 PdAg, PdAu and PdCu alloys in vacuum and under the acetylene partial hydrogenation conditions modeled by co-adsorption of H and acetylene and of H and ethylene. Our DFT-MC simulations indicate that Au and Ag segregate on the PdAu(111) and PdAg(111) surfaces while Pd is enriched on the PdCu(111) surface under vacuum conditions. The surface Pd contents of PdAg and PdAu tend to increase under partial hydrogenation conditions. Analyses reveal that the co-adsorption energies on the ideal (bulk-cut) surfaces correlate linearly with the values on the segregated surfaces and there is also a linear relationship for the d-band centers between the ideal and segregated surfaces. The present study provides a way to construct more realistic models for studying reactions on alloy surfaces.

Targeted recovery of Ag-Pd alloy from polymetallic electronic waste leaching solution via green electrodeposition technology and its mechanism

Electronic waste (e-waste), as hazardous waste, is a promising secondary resource of precious metals. The extraction of precious metals from e-waste has great environmental and economic benefits. Most of the existing methods have high energy consumption, environmental pollution or low recovery efficiencies. This study proposed the application of green electrodeposition technology to realize targeted recovery of Ag-Pd alloy from Ni, Cu, Ag, Pd, Bi polymetallic e-waste leaching solution. Linear sweep voltammetry was conducted to determine the feasibility of targeted extraction. The high purity of Ag-Pd alloy was realized by controlling the potential. The recovery efficiencies of Ag and Pd were 97.72% and 98.05% after 5 h in 0.5 mol/L HNO3 with applied potential of 0.35 V. The results indicated the formation of monophase Ag-Pd alloy. Besides, the effect of acidity and potential on the particle size of alloy was analyzed. Chronoamperometric method was applied to study the electrodeposition mechanism. The Ag-Pd electrodeposition followed three-dimensional instantaneous nucleation and growth mechanism analyzed with Scharifker-Hills model, thus producing a solid solution. The nucleation site increased with the overpotential. This study provides a novel, efficient and green approach for the targeted recovery of Ag and Pd from the complex multi-metal system of e-waste.

Synergistic effects between oil tribopolymerisation and abrasive wear in forming a protective third body in a conductive polymer/noble metal electrical contact

AbstractThe study of a sliding contact between a carbon‐particle filled polymer and a noble (AgPd) alloy, lubricated with a silicone oil/PTFE grease, has shown the formation of a third body in the interface. The electrical application of the system has required an in‐depth study of this third body to make sure that electrical conductivity was not endangered. Thanks to different chemical and electrical analyses, the third body, recognised as a tribofilm, can be described as a heterogeneous layer, composed mostly by transformed grease components and conductive wear particles. Coupling these observations and results from the literature, the formation mechanism is identified as tribopolymerisation by cross‐linking of the silicone oil molecules, analogous to the well‐known ‘gelation’ of silicone oils. The conditions for this phenomenon to occur in this system are discussed. Inclusion of wear particles from the conducting first bodies into the third body ensures low resistance: the tribofilm formed by this combination of mechanisms is a protective layer, which prevents polymer tracks from severe wear, without degrading electrical performance.

Isolated Pd atoms in a silver matrix: Spectroscopic and chemical properties.

Over the past decade, single-atom alloys (SAAs) have been a lively topic of research due to their potential for achieving novel catalytic properties and circumventing some known limitations of heterogeneous catalysts, such as scaling relationships. In researching SAAs, it is important to recognize experimental evidence of peculiarities in their electronic structure. When an isolated atom is embedded in a matrix of foreign atoms, it exhibits spectroscopic signatures that reflect its surrounding chemical environment. In the present work, using photoemission spectroscopy and computational chemistry, we discuss the experimental evidence from Ag0.98Pd0.02 SAAs that show free-atom-like characteristics in their electronic structure. In particular, the broad Pd4d valence band states of the bulk Pd metal become a narrow band in the alloy. The measured photoemission spectra were compared with the calculated photoemission signal of a free Pd atom in the gas phase with very good agreement, suggesting that the Pd4d states in the alloy exhibit very weak hybridization with their surroundings and are therefore electronically isolated. Since AgPd alloys are known for their superior performance in the industrially relevant semi-hydrogenation of acetylene, we considered whether it is worthwhile to drive the dilution of Pd in the inert Ag host to the single-atom level. We conclude that although site-isolation provides beneficial electronic structure changes to the Pd centers due to the difficulty in activating H2 on Ag, utilizing such SAAs in acetylene semi-hydrogenation would require either a higher Pd concentration to bring isolated sites sufficiently close together or an H2-activating support.

The influence of palladium on the hydrogenation of acetylene on Ag(111).

We have used reflection absorption infrared spectroscopy (RAIRS) and temperature programmed reaction (TPR) to study the selective hydrogenation of acetylene on both a clean Ag(111) surface and on a Pd/Ag(111) single-atom-alloy surface. The partial hydrogenation of acetylene to ethylene is an important catalytic process that is often carried out using PdAg alloys. It is challenging to study the reaction with ultrahigh vacuum techniques because H2 does not dissociate on Ag(111), and while H2 will dissociate at Pd sites, H-atom spillover from Pd to Ag sites does not generally occur. We bypassed the H2 dissociation step by exposing the surfaces to atomic hydrogen generated by the hot filament of an ion gauge. We find that hydrogen atoms react with acetylene to produce adsorbed ethylene at 85 K, the lowest temperature studied. This is revealed by the appearance of a RAIRS peak at 950 cm-1 due to the out-of-plane wagging mode of adsorbed ethylene when acetylene is exposed to a surface on which H atoms are pre-adsorbed. The formation of both ethylene and ethane are detected with TPR, but no acetylene coupling products, such as benzene, were found. From quantitative analysis of the TPR results, the percent conversion and selectivities to ethylene and ethane were determined. Low coverages of Pd enhance the conversion but do so mainly by increasing ethane formation.

In Situ Surface Structures of PdAg Catalyst and Their Influence on Acetylene Semihydrogenation Revealed by Machine Learning and Experiment.

PdAg alloy is an industrial catalyst for acetylene-selective hydrogenation in excess ethene. While significant efforts have been devoted to increase the selectivity, there has been little progress in the catalyst performance at low temperatures. Here by combining a machine-learning atomic simulation and catalysis experiment, we clarify the surface status of PdAg alloy catalyst under the reaction conditions and screen out a rutile-TiO2 supported Pd1Ag3 catalyst with high performance: i.e., 85% selectivity at >96% acetylene conversion over a 100 h period in an experiment. The machine-learning global potential energy surface exploration determines the Pd-Ag-H bulk and surface phase diagrams under the reaction conditions, which reveals two key bulk compositions, Pd1Ag1 (R3̅m) and Pd1Ag3 (Pm3̅m), and quantifies the surface structures with varied Pd:Ag ratios under the reaction conditions. We show that the catalyst activity is controlled by the PdAg patterns on the (111) surface that are variable under reaction conditions, but the selectivity is largely determined by the amount of Pd exposure on the (100) surface. These insights provide the fundamental basis for the rational design of a better catalyst via three measures: (i) controlling the Pd:Ag ratio at 1:3, (ii) reducing the nanoparticle size to limit PdAg local patterns, (iii) searching for active supports to terminate the (100) facets.

Electrochemical impedance spectroscopy study of corrosion characteristics of palladium-silver dental alloys.

Electrochemical impedance spectroscopy (EIS) has been used to obtain insight into corrosion processes for three Pd-Ag alloys, and compare their behavior with an Au-Pd alloy. Five specimens of each alloy received clinically-appropriate simulated porcelain-firing heat treatment. EIS testing was performed at ambient temperature, using 0.09% NaCl, 0.9% NaCl and Fusayama solutions. EIS data are presented as Bode plots. At the open-circuit potential (OCP), the data fit a modified Randles equivalent electrical circuit with a constant phase element (CPE), and the charge-transfer resistance (RCT ) and the two CPE parameters (CPE-T and CPE-P) were determined. The area-normalized capacitance of the double layer (Cdl ) was also calculated. The EIS data at two relevant elevated potentials in the passive range were also found to fit well a modified Randles equivalent circuit with different values for the charge transfer resistance and CPE parameters. At the OCP no significant effect on RCT was found for the alloys and electrolytes, and both alloy and electrolyte significantly affected CPE-P. In vitro corrosion was controlled by charge transfer and charge accumulation processes, and the behavior differed at the elevated potentials compared to the OCP. Significant effects were found for alloy, electrolyte, and alloy/electrolyte interaction on Cdl at the OCP. The EIS parameters at elevated potentials indicate that the Pd-Ag alloys should have satisfactory clinical corrosion resistance. The EIS analyses yielded information about in vitro corrosion of these alloys that cannot be obtained from potentiodynamic polarization testing.

Sintering mechanism of Ag-Pd nanoalloy film for power electronic packaging

Silver electrochemical migration causing short-circuit could be mitigated by Ag-Pd alloy. The conventional mechanical mixed Ag and Pd nanoparticles requires high alloying temperature as high as 850 °C. In this work, Ag20Pd nanoalloy film is prepared using pulsed laser deposition under room temperature as die attach material. After low temperature bonding at 300 °C, the bondline keeps in Ag20Pd alloyed state with a shear strength of 23.5 MPa (higher than MIL-STD-883 K, 7.8 MPa). The Ag20Pd nanoalloy exhibits superior resistance to Ag ionic migration with short-circuit time tripled than pure Ag sintered layer. A Ag-rich layer appears on the surface of Ag-Pd nanoalloy, although the Ag-Pd is the typical isomorphous alloy system. Molecular dynamics simulation reveals that Ag atoms (214.0 kJ/mol) diffuse easier than that of Pd atoms (234.6 kJ/mol) on the nanoalloy surface layer, while showing similar mobility for inner nanoalloy. The Ag-rich layer consisting of dynamic exchanging atoms has a prewetting effect and contributes to the neck formation among nanoparticles. This work sheds light on the sintering mechanism of Ag-Pd nanoalloy, and it is confirmed that Ag-Pd nanoalloy is promising for low temperature bonding in terms of the high reliability power electronic.