Pd Molar Ratio Research Articles

Plant-mediated synthesis of Au–Pd alloy nanoparticles supported on MnO2nanostructures and their application toward oxidation of 5-(hydroxymethyl)furfural

The bio-reduction of Au(iii) and Pd(ii) was first applied to the loading process. Au–Pd/MnO2was first applied in oxidation of HMF. The effects of Au–Pd molar ratio and the support morphology on the catalysis were discussed.

Kinetic analysis of the reduction of 4-nitrophenol catalyzed by Au/Pd nanoalloys immobilized in spherical polyelectrolyte brushes.

We present a detailed study of the catalytic activity of Au/Pd nanoalloys with Au : Pd molar ratio 75 : 25 synthesized using spherical polyelectrolyte brushes (SPB) as carrier system. The reduction of 4-nitrophenol (Nip) by sodium borohydride (BH4(-)) has been used as a model reaction. This reaction proceeds in two steps: 4-nitrophenol is first reduced to 4-hydroxylaminophenol which in a second step is reduced to the final product 4-aminophenol. Both steps of the reaction proceed on the surface of the nanoparticles (Langmuir-Hinshelwood-mechanism). We use this model to analyze the experimental data obtained by catalysis with the Au/Pd-nanoalloys. Good agreements between theory and experiments were found up to 30% conversion of Nip. The kinetic parameters were compared with the data derived from neat Au and Pd nanoparticles immobilized in the same SPB carrier system. The addition of 25% molar ratio of Pd to the nanoalloys increases the reaction rate of the first step nearly 10 times compared with that of SPB-Au and 60 times compared with that of SPB-Pd. Analysis of the nanoalloy by high-resolution transmission electron microscopy suggests that the surface defects of the nanoalloys play an important role for the enhanced catalytic activity.

Photochemical Synthesis and Characterization of Pd@Pt Core-Shell Nanoparticles with Low Cost and High Activity for Methanol Electro-catalytic Oxidation

Abstract In the PEG-acetone solution system, the Pd@Pt core-shell nanoparticles were prepared by photochemical reduction of Pt(IV) on the surface of Pd nanoparticles which were firstly in-situ synthesized as the seed by a photochemical method. The thickness of Pt shell of the composite particles could be efficiently adjusted by changing the molar ratio of Pd seed to Pt(IV). Core-shell composite structure of the obtained nanoparticles with average diameter in the range of 5.3∼7.1 nm was confirmed by HR-TEM and XPS. The electrochemical tests indicate that Pd@Pt core-shell nanoparticles, in which Pd: Pt is 1:1 or 1:4, have the similar catalytic activity and the stability to those of Pt, while lower cost. Therefore, they can be used for anode catalyst materials of direct methanol fuel cell.

Volcano-like behavior of Au-Pd core-shell nanoparticles in the selective oxidation of alcohols.

Gold-palladium (AuPd) nanoparticles have shown significantly enhanced activity relative to monometallic Au and Pd catalysts. Knowledge of composition and metal domain distributions is crucial to understanding activity and selectivity, but these parameters are difficult to ascertain in catalytic experiments that have primarily been devoted to equimolar nanoparticles. Here, we report AuPd nanoparticles of varying Au:Pd molar ratios that were prepared by a seed growth method. The selective oxidation of benzyl alcohol was used as a model reaction to study catalytic activity and selectivity changes that occurred after varying the composition of Pd in bimetallic catalysts. We observed a remarkable increase in catalytic conversion when using a 10:1 Au:Pd molar ratio. This composition corresponds to the amount of Pd necessary to cover the existing Au cores with a monolayer of Pd as a full-shell cluster. The key to increased catalytic activity derives from the balance between the number of active sites and the ease of product desorption. According to density functional theory calculations, both parameters are extremely sensitive to the Pd content resulting in the volcano-like activity observed.

Hybrid films of polyetherimide containingin situgrown Ag, Pd, and AgPd alloy nanoparticles: Synthesis route, morphology, and gas transport properties

In this study, bimetallic/polymer films are synthesized from polyetherimide (PEI), palladium acetate and silver nitrate for a wide range of total metal amount (from 0 to 30 wt %) and different Ag to Pd molar ratios. Hybrid precursor films are first prepared from polymer/metal complex solutions and the metal nanoparticles are then generated within the PEI matrix by annealing the precursor film under specific conditions. Reference neat PEI films and monometallic films are prepared in the same conditions. Interestingly, formation of AgPd alloys directly within the polymer films is for the first time obtained from a very simple and environmentally friendly route. Based on X-ray diffraction and transmission electron microscopy analyses, a nanostructuration mechanism is proposed. The interactions of hydrogen towards the nanocomposites are investigated and discussed as a function of the nanoparticle composition. The impact of the nanostructuration is also studied on H2, CO2, and He permeation properties. Significant improvement of barrier properties is achieved. The pertinent parameters of the gas transport are identified and modelled for each gas/composite system. Finally, from both morphological and gas transport analyses, it is concluded that in situ generation AgPd alloys with Pd to Ag ratio above 1 leads to very interesting and promising materials. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1211–1220

Au–Pd alloy nanoparticle catalyzed selective oxidation of benzyl alcohol and tandem synthesis of imines at ambient conditions

Alloy nanoparticles (NPs) of gold and palladium on ZrO2 support (Au–Pd@ZrO2) were found to be highly active in oxidation of benzyl alcohols and can be used for the tandem synthesis of imines from benzyl alcohols and amines via a one-pot, two-step process at mild reaction conditions. The first step of the process is oxidation of benzyl alcohol to benzaldehyde, excellent yields were achieved after 7h reaction at 40°C without addition of any base. In the second step, aniline was introduced into the reaction system to produced N-benzylideneaniline. The benzaldehyde obtained in the first step was completely consumed within 1h. A range of benzyl alcohols and amines were investigated for the general applicability of the Au–Pd alloy catalysts. It is found that the performance of the catalysts depends on the Au–Pd metal contents and composition. The optimal catalyst is 3.0wt% Au–Pd@ZrO2 with a Au:Pd molar ratio 1:1. The alloy NP catalyst exhibited superior catalytic properties to pure AuNP or PdNP because the surface of alloy NPs has higher charge heterogeneity than that of pure metal NPs according to simulation of density function theory (DFT).

Reducing Pt use in the catalysts for formic acid electrooxidation via nanoengineered surface structure

The design of active and durable catalysts for formic acid (FA) electrooxidation requires controlling the amount of three neighboring platinum atoms in the surface of Pt-based catalysts. Such requirement is studied by preparing Pt decorated Pd/C (donated as Pt–Pd/C) with various Pt:Pd molar ratios via galvanic displacement making the amount of three neighboring Pt atoms in the surface of Pt–Pd/C tunable. The decorated nanostructures are confirmed by XPS, HS-LEIS, cyclic voltammetry and chronoamperometric measurements, demonstrating that Pt–Pd/C (the optimal molar ratio, Pt:Pd = 1:250) exhibits superior activity and durability than Pd/C and commercial Pt/C (J-M, 20%) catalysts for FA electrooxidation. The mass activity of Pt–Pd/C (Pt:Pd = 1:250) (3.91 A mg−1) is about 98 and 6 times higher than that of commercial Pt/C (0.04 A mg−1) and Pd/C (0.63 A mg−1) at a given potential of 0.1 V vs SCE, respectively. The controlled synthesis of Pt–Pd/C lead to the formation of largely discontinuous Pd and Pt sites and inhibition of CO formation, exhibiting unprecedented electrocatalytic performance toward FA electrooxidation while the cost of the catalyst almost the same as Pd/C. These findings have profound implications to the design and nanoengineering of decorated surfaces of catalysts for FA electrooxidation.

Visible light enhanced oxidant free dehydrogenation of aromatic alcohols using Au–Pd alloy nanoparticle catalysts

We find that visible light irradiation of gold–palladium alloy nanoparticles supported on photocatalytically inert ZrO2 significantly enhances their catalytic activity for oxidant-free dehydrogenation of aromatic alcohols to the corresponding aldehydes at ambient temperatures. Dehydrogenation is also the dominant process in the selective oxidation of the alcohols to the corresponding aldehydes with molecular oxygen. The alloy nanoparticles strongly absorb light and exhibit superior catalytic and photocatalytic activity when compared to either pure palladium or gold nanoparticles. Analysis with a free electron gas model for the bulk alloy structure reveals that the alloying increases the surface charge heterogeneity on the alloy particle surface, which enhances the interaction between the alcohol molecules and the metal NPs. The increased surface charge heterogeneity of the alloy particles is confirmed with density function theory applied to small alloy clusters. Optimal catalytic activity was observed with a Au : Pd molar ratio of 1 : 186, which is in good agreement with the theoretical analysis. The rate-determining step of the dehydrogenation is hydrogen abstraction. The conduction electrons of the nanoparticles are photo-excited by the incident light giving them the necessary energy to be injected into the adsorbed alcohol molecules, promoting the hydrogen abstraction. The strong chemical adsorption of alcohol molecules facilitates this electron transfer. The results show that the alloy nanoparticles efficiently couple thermal and photonic energy sources to drive the dehydrogenation. These findings provide useful insight into the design of catalysts that utilize light for various organic syntheses at ambient temperatures.

Temperature-tunable catalytic property of Pd–M (Ag, Cu) bimetallic nanoparticles stabilized by thermal-sensitive PDEAm-g-PAN/PSt polymeric microspheres

Thermal-sensitive poly(N,N-diethylacrylamide) grafted poly(acrylonitrile/styrene) (PDEAm-g-PAN/PSt) polymeric microspheres were prepared from PDEAm macromonomer, St and AN by dispersion copolymerization. The polymeric microspheres had raspberry-like morphology with large surface area. Palladium–metal (Pd–M) (M: copper, Cu, silver, Ag) bimetallic nanoparticles were stabilized on the surface of the PDEAm-g-PAN/PSt microspheres via the coordinate interaction between amide groups in PDEAm and metal ions with the reduction of the corresponding ions. Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and thermogravimetry analysis (TGA) results confirmed the size and composition of the immobilized Pd–M nanoparticles. The Pd–M bimetallic nanoparticles showed superior catalytic efficiencies for the reduction of 4-nitrophenol (4-NP) than the monometallic nanoparticles. The catalytic activity of the Pd–M bimetallic catalysts could be controlled by the molar ratio of Pd and M ions and composition of Pd–M nanoparticles. Moreover, the catalytic property of the Pd–M nanoparticles could be regulated by temperature and increased with increasing the temperature above lower critical solution temperature (LCST). Furthermore, the Pd–M nanoparticles could be easily recycled and reused to catalyze 4-NP for five times without loss of activity. These bimetallic nanoparticles possess great potential in future practical application in catalytic technology.

Comparison of electrochemical properties of two-component C60-Pd polymers formed under electrochemical conditions and by chemical synthesis

The electrochemical behavior of C60-Pd polymer formed under electrochemical conditions and by the chemical synthesis was examined. In these polymers, fullerene moieties are covalently bonded to palladium atoms to form a polymeric network. Both materials deposited at the electrode surface show electrochemical activity at negative potentials due to the reduction of fullerene cage. Electrochemically formed thin polymeric films exhibit much more reversible voltammetric response in comparison to chemically synthesized polymers. The morphology and electrochemical behavior of chemically synthesized C60-Pd polymer depend on the composition of grown solution. Chemical polymerization results in formation of large, ca. 50 μm, crystallic superficial structures that are composed of regular spherical particles with a diameter of 150 nm. The capacitance properties of C60-Pd films were investigated by cyclic voltammetry and faradaic impedance spectroscopy. Specific capacitance of chemically formed films depends on the conditions of film formation. The best capacitance properties was obtained for films containing 1:3 fullerene to Pd molar ratio. For these films, specific capacitance of 35 Fg−1 was obtained in acetonitrile containing (n-C4H9)4NClO4. This value is much lower in comparison to the specific capacitance of electrochemically formed C60-Pd film.

The role of negatively charged Au states in aerobic oxidation of alcohols over hydrotalcite supported AuPd nanoclusters

The PVP-protected bimetallic gold–palladium nanoclusters (AuxPdy-PVP NCs) were prepared on the solid base hydrotalcite (HT) with various Au : Pd (x : y) molar ratios. Transmission electron microscopy showed narrow particle size distributions of AuxPdy-PVP NCs with a mean diameter in the range of 2.6–3.0 nm regardless of Pd content. Aerobic oxidations of 1-phenylethanol over the AuxPdy-PVP/HT catalysts showed that their catalytic activities were significantly affected by the Pd content. Correlations between charge transfer between Au and Pd and catalytic activity of the AuxPdy-PVP/HT catalysts were investigated with X-ray photoelectron spectroscopy (XPS), X-ray absorption near-edge structure (XANES), Michaelis–Menten kinetic studies for alcohol oxidation, and other analytical techniques. The peaks of Au 4f in the XPS spectra were shifted to the lower energy side with increase of Pd content, indicating the electron transfer from Pd to Au atoms according to Pauling's electronegativity protocol. The electron densities in the Au 5d orbital in the AuxPdy-PVP/HT catalysts estimated by the Au L3-XANES spectra correlated well with their catalytic activities. Moreover, the kinetic studies also proposed that the electron rich Au 5d states, resulting from the intermetallic electron transfer from Pd atoms, strongly contributed to the rate-determining step in the alcohol oxidation. It was concluded that the electronic negativity of the Au 5d states controlled by the Pd content accelerated the rate-determining step in alcohol oxidation through highly active radical-like intermediates.

High electrocatalytic effect of Au–Pd alloy nanoparticles electrodeposited on microwave assisted sol–gel-derived carbon ceramic electrode for hydrogen evolution reaction

Various Au–Pd bimetallic nanoparticles were electrodeposited on microwave irradiated carbon ceramic electrodes (MWCCE). Au:Pd molar ratios of 75:25, 50:50 and 25:75 were electrodeposited on MWCCE and their electrocatalytic activities for hydrogen evolution reaction (HER) were evaluated. Among them, the alloy with Au:Pd molar ratio of 25:75 showed highest electrocatalytic activity for HER. The structure and nature of these alloys were characterized by scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, inductively coupled plasma, and cyclic voltammetry. Alloying degree of bimetallic nanoparticles and electrodeposition time were optimized. The electrocatalytic activity of bimetallic nanoparticles was also compared with individual non-alloyed Au and Pd catalysts and the results showed that alloy nanoparticles have higher electrocatalytic activity for hydrogen evolution. The Tafel slopes ranges are obtained from 136 mV dec−1 to 165 mV dec−1 for HER on bare and modified MWCCE and kinetic parameters show that the Volmer step must control the HER. The stability of the best electrode is determined by chronopotentiometric and it showed a good stability.

Applicability of a catalytic reduction method using a palladium–copper catalyst and hydrazine for the denitration of a highly concentrated nitrate salt solution

Denitration of a highly concentrated sodium nitrate (NaNO3) aqueous solution via a catalytic reduction method using a palladium–copper catalyst supported on carbon powder (Pd–Cu/C) and hydrazine (N2H4) was investigated. It was demonstrated that nitrate ion (NO3 −) in a 5 mol L−1 NaNO3 solution was completely reduced through an intermediate nitrite ion (NO2 −) to nitrogen compounds such as nitrogen, nitrous oxide, and ammonia. By comparing the reaction rates of NO3 − and NO2 − obtained using catalysts with various Pd–Cu compositions and different reductants (hydrogen (H2) or N2H4), it was determined that the catalyst with a molar ratio of Pd:Cu = 1:0.66 provides the maximum reaction rates for NO3 − and NO2 − using N2H4, and that not only the reactions of NO3 − and NO2 − but also that of N2H4 were affected by the Pd–Cu composition.

Homo‐ and copolymerization of norbornene and 5‐norbornene‐2‐yl acetate with bis‐(β‐ketonaphthylamino)palladium(II)/B(C6F5)3 catalytic system

AbstractThe polymerization of norbornene with bis(β‐ketonaphthylamino) palladium(II), Pd{CH3C(O)CHC[N(naphthyl)]CH3}2, in combination with tris(pentafluorophenyl)borane (B(C6F5)3), was investigated by varying the B:Pd(II) molar ratio, monomer concentration, reaction temperature, and time. The catalytic activity was found to reach 2.8 × 104 gPolymer/(molPd•h) and the obtained polynorbornene (PNBE) was confirmed to be vinyl addition polymer and showed good thermo‐stability (Tdec > 350°C), but exhibited poor solubility in organic solvents due to the relative higher stereo regularity. Pd{CH3C(O)CHC[N(naphthyl)]CH3}2/B(C6F5)3 system is also an active catalyst for copolymerization of norbornene and 5‐norbornene‐2‐yl acetate (NBE‐OCOCH3) in toluene with moderate yields (in 9.2–36.5% yields) and produces the addition‐type copolymer with relatively high molecular weights (0.96 × 104–2.13 × 104 g/mol). The incorporation of functional group in the copolymer can be controlled up to 0.9–23.5 mol% by varying the NBE‐OCOCH3 monomer feed ratios from 10 to 90%. The copolymers are proved to be noncrystalline and show good solubility in common organic solvents and excellent thermal stability up to 350°C. Copyright © 2011 John Wiley & Sons, Ltd.

Characteristics of nano-sized Ag-Pd (70-30)-glass composite powders prepared by flame spray pyrolysis

Nano-sized Ag–Pd alloy and Ag–Pd–glass composite powders were prepared by flame spray pyrolysis. The Ag–Pd molar ratio was fixed at 70–30. The mean sizes of the Ag–Pd and Ag–Pd–glass powders were 29 and 25 nm, respectively. The Ag–Pd alloy powder began to be oxidized rapidly at approximately 365°C and oxidation of alloy powders was finished at 420°C. On the other hand, oxidation of the Ag–Pd–glass composite powders gradually occurred around 400°C and oxidation of the powders was finished at 530°C. The specific resistances of the conducting films formed from the nano-sized Ag–Pd–glass composite powders were 76, 59, 35 µΩ·cm at firing temperatures of 550, 600 and 800°C, respectively.

In-Situ Loading Ultrafine AuPd Particles on Ceria: Highly Active Catalyst for Solvent-Free Selective Oxidation of Benzyl Alcohol

Ce(III) oxide was synthesized under the protection of nitrogen gas, which had strong ability to reduce noble metal ions (e.g., Au, Pd ions) into metallic forms under oxygen-free conditions. On the basis of the surface redox reaction between the Ce(III) oxide support and noble metal ions, an effective and novel approach was presented to prepare noble metal/CeO(2) nanocatalysts, and a series of AuPd/CeO(2) nanocomposites with different Au:Pd molar ratios and metal loadings were obtained in the absence of any extra reducing and protective agents. The resultant composites were characterized by different techniques including X-ray diffraction, transmission electron microspectroscopy, X-ray photoelectron microspectroscopy, and ICP-AES analysis. It was demonstrated that in the AuPd/CeO(2) composites the content of Ce(III) reached about 30%, and the AuPd bimetallic particles with average size of 2.6 or 3.3 nm and narrow size distribution were uniformly distributed on the CeO(2) nanorods. The AuPd/CeO(2) composites were found to be excellent heterogeneous nanocatalysts for the selective oxidation of benzyl alcohol under solvent-free conditions. It was shown that all the AuPd/CeO(2) catalysts exhibited good selectivity toward benzaldehyde; especially, the catalyst with Au:Pd = 1:5 and metal loading of 1.2 wt % displayed extremely high activity with a TOF = 30.1 s(-1) at 160 °C.

Au–Pd alloying-promoted thermal decomposition of PdO supported on SiO 2 and its effect on the catalytic performance in CO oxidation

We have prepared a series of Au–Pd/SiO 2 catalysts by the routine deposition–precipitation method followed by calcination at 200 °C in air for 4 h. The structures of these catalysts have been characterized with powder X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and H 2-temperature-programmed reduction. Their catalytic activity in CO oxidation has also been studied. We found that the preparation procedure leads to the formation of highly dispersed PdO supported on SiO 2 in Pd/SiO 2, but to the formation of both highly dispersed PdO and Au x Pd alloy nanoparticles in Au–Pd/SiO 2 catalysts. The fraction of metallic Pd in Pd species increases with the increase of Au:Pd molar ratio in Au–Pd/SiO 2 catalysts. We proposed that the alloying of Au and Pd can promote the thermal decomposition of PdO supported on SiO 2. Because of the existence of metallic Pd, Au–Pd/SiO 2 catalysts are more active in CO oxidation than Pd/SiO 2. Au–Pd/SiO 2-0.5 exhibits the same activity as Pd/SiO 2-H 2 in CO oxidation. Our results provide some novel information on the fabrication of supported Au x Pd alloy nanoparticles.

Solvent-free aerobic oxidation of benzyl alcohol over Pd monometallic and Au–Pd bimetallic catalysts supported on SBA-16 mesoporous molecular sieves

Pd monometallic and Au–Pd bimetallic catalysts supported on surface-functionalized SBA-16 were prepared by a conventional adsorption method and were examined using X-ray diffraction, nitrogen physisorption, UV–vis spectroscopy, and high-resolution transmission microscopy. SBA-16 with the unique “super-cage” structure effectively controlled the formation of dispersed noble metal nanoparticles in the mesoporous channels. These confined nanoparticles with a narrow particle size distribution exhibited excellent catalytic activity in the solvent-free benzyl alcohol selective oxidation with molecular oxygen. Amine-functionalization remarkably improved the selectivity towards benzaldehyde. Au–Pd bimetallic catalysts showed enhanced catalytic performance compared to the Au and Pd monometallic catalysts. The highest turnover frequency of 8667 h −1 was achieved over a bimetallic catalyst with Au:Pd molar ratio of 1:5; this good catalytic activity can be maintained after five recycling runs. The characterization results of scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy revealed that the bimetallic catalyst was constructed of uniformly alloyed nanoparticles with Pd cluster-on-Au cluster structure. The synergetic effect between Au and Pd nanocluster was suggested to account for the better catalytic activity of bimetallic catalysts because the size-dependent effect can be ruled out due to the effective confinement of noble metal nanoparticles by SBA-16 mesostructure.

The choice of an optimal composition and preparation method of non-promoted Pd/Al2O3 and promoted Pd-Co/Al2O3 catalysts for the selective hydrogenation of vinylacetylene

For the purpose of optimizing the chemical composition and technology of synthesis of the catalyst for the acetylene hydrocarbons hydrogenation in industrial streams of butadiene and ethyl-vinylacetylene fractions, the influence of the palladium initial compound nature, the active component concentration, the promotion by cobalt, the molar ratio of palladium to cobalt, the phase composition of the supporter on physical chemical properties, and the activity and selectivity to 1,3-butadiene of the catalysts was studied. The effect of acidic-base characteristics of the supporter on its ability to oligomerize unsaturated hydracarbons has been investigated. It has been established, than the δ-Al2O3 supporter is characterized by a low concentration of Bronsted and Lewis acidic sites, decreasing the quantity of oligomers formed on its surface. The optimal composition of the non-promoted KGV-07 catalyst, recommended for the raw butadiene fraction hydrogenation, is 0.5% of Pd deposited from palladium acetate on δ-Al2O3 with palladium particles of 16 nm in size, on which the vinylacetylene conversion of 100% and the selectivity to 1,3-butadiene of 69.9% are reached at a temperature of 20°C at the reactor input, hourly space velocity (HSV) of hydrocarbon raws of 700 h−1, molar ratio of hydrogen to ethyl-vinylacetylenes of 4: 1, summary concentration of 49% of acetylene hydrocarbons, and 1.5% of 1,3-butadiene in hydrocarbon raws. The synthesis of the cobalt-promoted KGVP-07 catalyst with 0.5% of Pd deposited from palladium acetylacetonate on δ-Al2O3 and molar ratio of Pd: Co = 1: 1 has been developed for the hydrogenation of an ethyl-vinylacetylene fraction with a concentration of acetylene hydrocarbons to 6 wt %, with the vinylacetylene conversion of 100% and the selectivity to 1,3-butadiene of 61.3%, at HSV of the hydrocarbon stream of 700 h−1, temperature of 6°C at the reactor input, and molar ratio of hydrogen to ethyl-vinylacetylene admixtures of 4: 1. Promotion by cobalt leads to the formation of palladium particles at the zero oxidation level and to an increase in their average size from 11 to 14 nm in comparison with the non-promoted Pd-catalyst. In the work, IR-spectroscopy, transmission electron microscopy (TEM), and physicochemical methods have been used to characterize the catalysts texture and supporter phase composition. Pilot tests of the KGV-07 and KGVP-07 catalysts on the Etilen plant unit have proven the correctness of the choice for the catalysts’ optimal chemical composition.

Thermodynamic description of the ternary Pd–Sn–Zn system

Abstract The thermodynamic properties of the liquid Pd–Sn–Zn ternary system were investigated, because the Sn–Zn alloy is a promising lead-free solder and Pd can be used as a substrate material. Using an appropriate galvanic cell, the partial free energies of Zn in liquid Pd–Sn–Zn alloys were determined as a function of concentration and temperature. Thermodynamic properties were obtained for 18 alloys. Their composition was situated on two cross-sections with the constant molar ratios of Pd: Sn = 1:3 and 1:9. The integral Gibbs free energy and the integral enthalpy for the ternary system at 1000 K were calculated by Gibbs–Duhem integration. For the liquid binary Pd–Sn system, some inconsistencies were found in previous CALPHAD results. Considering the latest experimental information, the interaction parameters of the liquid phase were reevaluated. The liquidus temperatures were also determined from EMF measurements.