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ABSTRACT In this research, bimetallic CdNi nanoparticles encapsulated in a magnetic spent coffee ground (Fe3O4@COFF/CdNi) was synthesized as a new nanocatalyst. The structural and chemical characteristics of Fe3O4@COFF/CdNi were comprehensively investigated using various techniques, including FT‐IR, XRD, XPS, TEM, VSM, EDS, TGA, BET, and ICP. Through XRD, XPS analysis, TEM images, and EDS mapping, the presence of CdNi nanoalloys was conclusively established. Fe3O4@COFF/CdNi exhibited remarkable catalytic activity for the hydrogen generation from water using iso‐propanol as a clean sacrificial agent. The high catalytic performance of Fe3O4@COFF/CdNi was attributed to the synergistic cooperative effect of Cd and Ni within CdNi nanoalloys. Interestingly, this process was performed for the in situ generated hydrogen from water to reduce a range of nitrobenzenes simultaneously into the corresponding anilines in high yields (93%–98%). The magnetic and hydrophilic characteristics of Fe3O4@COFF/CdNi facilitated its reusability over five runs. Using water as the most abundant hydrogen source, for the first time for in situ hydrogen generation–reduction of nitrobenzenes without demanding on external light sources or power supplies can be mentioned as a significant milestone of this field of study. [ABSTRACT FROM AUTHOR]

The structures and dynamical properties of core–shell bimetallic Ni-Ag nanoalloys varying with different sizes and compositions have been studied using Monte Carlo (MC) and Molecular Dynamic (MD) simulations. We have considered the compositions in which the size of the core increases while the total number of atoms is fixed. In this sense, two (Ni13Ag134, Ni55Ag92), three (Ni13Ag296, Ni55Ag254, Ni147Ag162) and four (Ni13Ag548, Ni55Ag506, Ni147Ag414 and Ni309Ag252) compositions were considered for 147, 309 and 561 atoms, respectively. Highly symmetric Mackay icosahedral structures with centred symmetric cores appear for these specific sizes and compositions. Also, smaller Ni atoms tend to occupy the core and Ag atoms prefer to segregate to the surface of the nanoalloy due to its lower surface and cohesive energy. Then, the lowest energy structures obtained by Basin Hopping MC simulations were used as initial configurations for melting simulations. The transitions between different chemical ordering patterns with increasing temperature are possible in these systems while they are still in the solid state. Although there are clear differences in the melting process of the compositions with increasing size of the core, for all cases, surface melting occurs indicating that the Ag shell melts before the inner Ni core. [ABSTRACT FROM AUTHOR]

Features of the catalytic action of Pd–Ag, Pd–Cu, Pd–Au, Pd–Ga, and Pd–Zn bimetallic systems on the acetylene conversion to ethylene are discussed taking into account two factors that determine the effect of the second metal on palladium, namely, the "ensemble effect" (geometric effect) and the "ligand effect" (electronic effect). The relationship between the calculated thermodynamic and kinetic parameters of the adsorption interaction of major reaction medium components and intermediates with the catalyst surface, the structure of active ensembles, and characteristics determined in tests, such as the structural parameters of bimetallic phases, the electronic state of their components, and catalytic properties, is shown. Some examples are given to show that the modifier atoms can be incorporated into active ensembles and the sites formed by the modifier atoms can be involved in the catalysis of individual elementary steps. [ABSTRACT FROM AUTHOR]

The recent applications discovered in the use of silver and bismuth nanoalloys, as well as the new environmentally friendly techniques used in their production, have aroused the interest of the scientific community in this study. In this study, we used ab initio density functional theory (DFT) implemented in the Quantum Espresso software to study the structural and electronic properties of silver icosahedral clusters with a bismuth atom by maintaining a similar percentage of bismuth in the existing nanoparticles (∼ 6%). The results indicate a decrease in the magnetization of the cluster with bismuth both in the lateral and central positions, going from 5 [μB] in the silver cluster to 3 [μB], and also to a distortion of the structure that leads to a doubling of energy levels, associated with a Jahn–Teller effect, when the bismuth atom was positioned in the lateral position, bringing the structure to a state of lower energy, which agrees with the experimental results. [ABSTRACT FROM AUTHOR]

The main goal of the current work is to develop external excellence, hardness, and anti-corrosion quality materials for engineering and metal finishing applications. To design and prepare a binary type of Zn-Ag nanoparticles as an alloy substantial over on mild steel (MS) engineering substrate using direct current (DC) electrochemical deposition. In this regard, silver nanoparticles are evenly distributed throughout the pure zinc with high-quality surface. Some different bath compositions, experimental settings, and parameters are used to optimize Zn-Ag nanoalloy coatings. The prepared specimen is examined using energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscope (FE-SEM), and X-ray diffraction (XRD). The XRD data for the AgZn3 phase demonstrate well-crystalline properties with reference pattern JCPDS 00–025-1325. Investigations are conducted into electrochemical research, including the Tafel corrosion test and electrochemical impedance spectroscopy (EIS). The results showed AgZn3 and Zn lower values of Icorr (1 × 10−5 A cm−2) compared to the Zn (1 × 10−3) sample, a greater corrosion potential (Ecorr) of − 0.9 V and − 0.6 V, respectively, when deposited on MS substrate. For technical and automotive applications, the produced AgZn3 on MS therefore shows the optimum corrosion resistance and hardness surface with compact microstructure. [ABSTRACT FROM AUTHOR]

Developing highly active catalysts for the decomposition of ammonia to produce hydrogen is an important goal in the context of renewable energy. Allied with this is a need for identification strategies to efficiently design novel catalysts integral to ensuring rapid progress in this research field. We investigated the efficacy of N–binding energy and periodic table interpolation to predict active bimetallic nanoparticle catalysts. Supported iron-platinum and iron-palladium were identified and experimentally shown to be more active than their monometallic analogues. Atomic resolution electron microscopy indicated that the most active catalyst (5 wt% Fe80Pt20/γ-Al2O3) was principally formed of alloyed nanoparticles. It restructured during testing, yet no activity loss was noted at 20 h time-on-line. While these findings show that periodic table interpolation may be a viable tool for identifying active combinations of metals, the activity of the catalysts in the current work were not able to outperform the Ru/Al2O3 benchmark. Further catalyst optimization or refinement of reaction descriptors may facilitate the development of catalysts with higher intrinsic activity than the current state-of-the-art catalysts. [ABSTRACT FROM AUTHOR]

The research field of plasma–liquid interactions is quickly expanding due to its great potential in many applications, including nanomaterial synthesis. In this paper, we present a novel kind of in-liquid discharge that is generated at or near the interface of two immiscible liquids, water and liquid hydrocarbon. The optical emission characteristics of this discharge are studied using ICCD imaging, and their dependence on the position of the interface with respect to the electrode are analyzed. The results show that when the electrode is at the interface, discharge efficiency is optimal due to increased discharge probability and plasma volume. Moreover, when the electrical conductivity of the solution is increased beyond ~ 500 µS/cm, the discharge mode transits from streamer to spark. Analysis of the nanomaterial produced by interfacial discharges reveals that when the discharge is ignited at the interface of distilled water-heptane, amorphous carbonaceous sheet-like materials are formed; however, when Ni-nitrate is added to raise the electrical conductivity of water, Ni nanoparticles embedded in C-matrix are synthesized. Furthermore, the particle surface density in the C-sheet increases at higher electrical conductivity. As the discharge transits from streamer (low conductivity) to spark (high conductivity), the amorphous C-sheet becomes graphitized. When two or three salts (Ni-, and/or Co-, and/or Fe- nitrate) are added at the high conductivity condition (5000 µS/cm), nanoalloys (NiCo, NiFe, CoFe, and NiCoFe) embedded in C-matrix are formed. Overall, the data reported herein demonstrates interfacial discharges in liquid offer great opportunities for efficiently and ecologically synthesizing novel nanomaterials with unique properties. [ABSTRACT FROM AUTHOR]

Utilizing plant extracts in the green synthesis of bimetallic nanoalloys receives more attention due to its eco-friendly, cheap, single-step, easy-handling method, producing highly active and biocompatible nanoalloys. Therefore, the aqueous extract of ginger rhizome was used to form bimetallic gold/silver (Au/Ag) nanoalloys. There were 37.3 mg.g−1 of total soluble carbs, 0.75 mg.g−1 of proteins, and 0.03 mg.g−1 of phenolic compounds quantified in ginger rhizome. The production of BAu/Ag-NPs relies on these components. The as-formed BAu/Ag-NPs were characterized using UV–Vis spectroscopy. The results showed that the peak surface plasmon resonance (SPR) occurred between 440 and 545 nm. The existence of several functional groups involved in the reduction and stability of the generated nanoalloys was shown by Fourier-transform infrared (FT-IR). The nanoalloys, with an average size of 49.1 ± 16.2 nm, were observed to be spherical using transmission electron microscopy (TEM). Energy-dispersive X-ray (EDX) indicated that the synthesized nanoalloy mainly consisted of Au and Ag ions, which made up (31.2 % and 47.1 %) and (45.9 % and 28.6 %) of the sample’s atomic and weight percentages, respectively. The crystallography of the nanoalloys was confirmed using XRD analysis. When examined for their capacity to suppress viral replication, the synthesized nanoalloys showed remarkable results, with 78.2 % inhibition against HAV and 69.6 % against Cox-B4. In addition, the anticancer activity of nanoalloys against oral epithelial cells (OEC), MCF7 adenocarcinoma cells, and HepG2 hepatocarcinoma cells was investigated using the MTT assay method. While the nanoalloys exhibited moderate toxicity towards normal OEC (IC50: 502.5 ± 2.8 g.mL−1), they showed substantial cytotoxicity towards cancer cells, MCF7 and HepG2, with IC50 values of 212.6 ± 4.4 and 117.9 ± 6.6 µg.mL−1, respectively. According to these data, BAu/Ag nanoalloys show potential as antiviral and anticancer drugs that selectively kill cancer cells.

Gold and silver are, for all their chemical similarities, optically very different. Small Ag clusters show a localized surface-plasmon resonance (LSPR), whereas in Au clusters smaller than about 300 atoms, the resonance is absent due to the coupling with the interband transitions from the d electrons. This opens the possibility of tuning the cluster properties depending on their composition and chemical configuration. Earlier work on AgAu alloy clusters has shown that the outermost shell of atoms is crucial to their overall optical properties. In the present contribution, we consider the optical spectroscopic properties associated with the structural rearrangement in 55-atom AgAu alloy clusters in which the core transforms from pure silver to pure gold. Calculations using time-dependent density-functional theory are complemented by an in-depth study of the subtle effects that the chemical configuration has on the details of the materials’ d bands. Although the cluster surface remains alloyed, the geometrical changes translate into strong variations in the optical properties.

Gold and silver are, for all their chemical similarities, optically very different. Small Ag clusters show a localized surface-plasmon resonance (LSPR), whereas in Au clusters smaller than about 300 atoms, the resonance is absent due to the coupling with the interband transitions from the d electrons. This opens the possibility of tuning the cluster properties depending on their composition and chemical configuration. Earlier work on AgAu alloy clusters has shown that the outermost shell of atoms is crucial to their overall optical properties. In the present contribution, we consider the optical spectroscopic properties associated with the structural rearrangement in 55-atom AgAu alloy clusters in which the core transforms from pure silver to pure gold. Calculations using time-dependent density-functional theory are complemented by an in-depth study of the subtle effects that the chemical configuration has on the details of the materials' d bands. Although the cluster surface remains alloyed, the geometrical changes translate into strong variations in the optical properties. [ABSTRACT FROM AUTHOR]

Copper homometallic and copper-rich heterometallic nanoclusters with some Cu(0) character are reviewed. Their structure and stability are discussed in terms of their number of "free" electrons. In many aspects, this structural chemistry differs from that of their silver or copper homologs. Whereas the two-electron species are by far the most numerous, only one eight-electron species is known, but more electron-rich nanoclusters have also been reported. Owing to the relatively recent development of this chemistry, it is likely that more electron-rich species will be reported in the future. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the antifungal activity of copper-boron (Cu-B) nanoalloys against a range of Phytophthora species, including P. capsici, P. citrophthora, P. palmivora, P. cinnamomi, P. nicotianae, P. cactorum, P. plurivora, P. inundata, and P. megasperma. The nanoalloys were synthesized via mechanical alloying under an argon atmosphere, resulting in the formation of nanocrystalline Cu-B nanoalloys with irregular morphology and particle sizes ranging from 50 to 240 nm. At a concentration of 250 µg mL−1, the Cu-B nanoalloys demonstrated complete inhibition of mycelial growth, sporangium production, and zoospore germination in all tested Phytophthora species. The EC50 values for mycelial growth ranged from 28.02 to 120.17 µg mL−1, while for sporangium production and zoospore germination, they were below 10 µg mL−1. Furthermore, the nanoalloys exhibited fungicidal activity against specific Phytophthora species, such as P. capsici, P. citrophthora, P. inundata, and P. megasperma, at concentrations of 100, 250, 250, and 250 µg mL−1, respectively. Notably, the Cu-B nanoalloys displayed significant protective and curative effects on tuber rot severity in P. nicotianae-inoculated potatoes, resulting in reductions of 94.13% and 92.61% compared to the control, respectively, at a concentration of 10 µg mL−1 (P < 0.05). These findings highlight the potential of Cu-B nanoalloys as a promising fungicide for the management of plant diseases caused by Phytophthora spp. [ABSTRACT FROM AUTHOR]

The article reveals for the first time the features of nanoparticle morphology, phase compositions, and their changes when heating FePt and CoPt nanoalloys. Nanoparticles were obtained by co-reduction of precursor solution mixtures with hydrazine hydrate. The features were found by a complex of methods of X-ray diffraction (in situ XRD and X-ray scattering), TEM HR, and cyclic voltammetry. In addition, adsorbometry results were obtained, and the stability of different nanocluster structures was calculated by the molecular dynamics method. There were only FCC solid solutions in the X-ray patterns of the FePt and CoPt nanoalloys. According to XRD, in the case of nanoparticle synthesis with Fe and Co content less than 10 at. %, the composition of solid solutions was close to or practically equal to the composition of the as-synthesized nanoparticles quantified by inductively coupled plasma optical emission spectrometry. For systems synthesis with Fe and Co content greater than the above, the solubility limits (SLs) of Fe and Co in Pt were set 11.4 ± 0.7 at. % and 17.5 ± 0.6 at. %, respectively. Therefore, there were non-registered XRD extra-phases (XRNDPh-1) in the systems when CFe,Co ≥ SL. This statement was supported by the results of TEM HR and X-ray scattering: the smallest nanocrystals (1–2 nm) and amorphous particles were found, which qualitatively agreed with the sorbometry and SAXS results. Molecular dynamics calculations of stability for FePt and CoPt alloys claimed the structures of the most stable phase corresponded to phase diagrams (A1 and L12). Specific peculiarities of the morphology and compositions of the solid solutions of nanoalloys were established: structural blockiness (domain) and composition heterogeneity, namely, platinum enrichment of internal (deep) layers and homogenization of the nanoalloy compositions at relatively low temperatures (130–200 °C). The suggested model of the formation of nanoalloys during the synthesis, qualitatively, was compliant with the results of electrochemical deposition of FePt films on the surface of various electrodes. When nanocrystals of solid solutions (C(Fe, Co) < SL) were heated above specific temperatures, there were phase transformations with the formation of two-phase regions, with solid solutions enriched with platinum or iron (non-registered XRD phase XRNDPh-2). The newly formed phase was most likely intermetallic compounds, FePt3, CoPt3. As a result of the study, the model was developed, taking into account the nanoscale of the particles: XRDPh (A1, FeaPt1−a) → XRDPh (A1, Fem×a−xPtm−m×a+x) + XRNDPh-2 (Fen×a+yPtn−n×a−y) (here, m + n = 1, m ≤ 1, n ≤ 1). [ABSTRACT FROM AUTHOR]

Nanomedicine relies on the exploitation of nanoscale constructs for therapeutic and diagnostic functions. Gold and gold–iron alloy nanoparticles (NPs) are two examples of nanomaterials with favorable features for use in nanomedicine. While gold NPs have been studied extensively in the last decades, they are not biodegradable. Nonetheless, biodegradation was recently observed in gold alloys with iron obtained using laser ablation in liquid (LAL). Hence, there is a significant interest in the study of the biological effects of gold and gold–iron alloy nanoparticles, starting from their tolerability and cytotoxicity. In this study, these two classes of NPs, obtained via LAL and coated with biocompatible polymers such as polyethylene glycol, were investigated in terms of their cytotoxicity in fibroblasts, prostate cancer cells (PC3) and embryonic kidney cells (HEK). We also explored the effects of different synthetic procedures, stabilizing additives, and the possible mechanisms behind cell mortality such as the formation of reactive oxygen species (ROS) or ferroptosis. NPs larger than 200 nm were associated with lower cell tolerability. The most tolerable formulations were pure PEG-Au NPs, followed by PEG-Au–Fe NPs with a hydrodynamic size < 50 nm, which displayed a toxicity of only 20% in fibroblasts after 72 h of incubation. In addition, tumor cells and highly proliferating HEK cells are more sensitive to the NPs than fibroblasts. However, a protective effect of catalase was found for cells incubated with PEG-Au–Fe NPs, indicating an important role of hydrogen peroxide in alloy NP interactions with cells. These results are crucial for directing future synthetic efforts for the realization of biocompatible Au NPs and biodegradable and cytocompatible Au–Fe alloy NPs. Moreover, the correlation of the cytocompatibility of NPs with ROS and ferroptosis in cells is of general interest and applicability to other types of nanomaterials. [ABSTRACT FROM AUTHOR]

Using seleno-compounds and telluric compounds is a practical approach for developing solutions against drug-resistant bacterial infections and malignancies. It will accelerate the search for novel treatments or adjuvants for existing therapies. Selenium and tellurium nanospheres can be produced by lactic acid bacteria. The bacteria can differentiate the selenium and tellurium when the medium contains both selenite and tellurite. Therefore, our question in this study was the following: are they making alloys from the selenium and tellurium and what will be the composition, color, and shape of the nanoparticles? We used a simple microbial synthesis to produce nanoselenium, nanotellurium, and their alloys from sodium selenite and sodium tellurite using Lactobacillus casei. This bacterium produced red spherical amorphous elemental selenium nanospheres with a diameter of 206 ± 33 nm from selenite and amorphous black nanorods with a length of 176 ± 32 nm and a cross-section of 62 ± 13 nm from tellurite. If the initial medium contains a mixture of selenite and tellurite, the resulting nanoparticles will contain selenium and tellurium in the same ratios in the alloy as in the medium. This proves that Lactobacillus casei cannot distinguish between selenite and tellurite. The shape of the nanoparticles varies from spherical to rod-shaped, depending on the ratio of selenium and tellurium. The color of nanomaterials ranges from red to black, depending on the percentage of selenium and tellurium. These nanomaterials could be good candidates in the pharmaceutical industry due to their antipathogenic and anticarcinogenic properties. [ABSTRACT FROM AUTHOR]

Alkaline water electrolysis system is of general interest but is impeded by the unsatisfactory hydrogen evolution reaction (HER) performance under ampere‐level current density. Herein, the synchronous modification of complicated Volmer/Tafel kinetics is effectuated for attaining ampere‐level current density hydrogen production via engineering double‐tuned RuCo nanoalloy and dual metal single atoms on hierarchical N‐doped mesoporous carbon (RuCo@RuSACoSA‐NMC). The electronic structure of Ru sites in dual metal single atoms can be synergistically tailored by adjacent Co atomic sites and nanoalloy, which makes it achieve faster Volmer kinetics with rapid water adsorption/dissociation and transfer rates toward adsorbed hydroxyl. While double‐tuned Ru sites in nanoalloy by adjacent alloyed Co sites and dual metal single atoms undertake optimized Tafel kinetics with boosted transfer rates toward adsorbed hydrogen. Accordingly, RuCo@RuSACoSA‐NMC exhibits ultralow HER overpotential of 255 mV at 1 A cm−2 with robust stability over 24 days, ultrahigh mass activity of 37.2 A mgRu−1, and turnover frequency of 19.5 s−1. More importantly, RuCo@RuSACoSA‐NMC can make water electrolysis system possess low power consumption of 5.34 kWh per Nm3H2 and estimated costs of 1.197 $ per kgH2. The concept emphasized in this study provides guidance for rational design of cost‐effective catalysts with ampere‐level current density hydrogen production. [ABSTRACT FROM AUTHOR]

ABSTRACTThe deformation of interatomic distances with respect to those of the perfect crystal generates atomic-level strain. In nanoalloys, strain can arise because of finite size, morphology, domain structure and lattice mismatch between their atomic compounds. Strain can strongly affect the functional properties of nanoalloys, as it alters their electronic energy levels. Moreover, atomic-level strain generates atomic-level stress, which in turn results in distortions induced by strain. When the stress accumulated in a nanoalloy exceeds a certain level, the particle can relax that stress by undergoing structural transitions such as shape and/or chemical ordering transitions. Atomic-level strain is then a powerful tool to control and manipulate the structural and functional properties of nanoalloys. This requires a combined theoretical and experimental approach both to deeply understand the physical origin of strain, and to characterize it with a sub-angstrom resolution. Here, we present a theoretical analysis of the main sources of strain in nanoalloys, we analyse how atomic-level strain can be experimentally measured with transmission electron microscopy, we discuss its effect on the functional properties of nanoalloys, finally we describe how atomic-level stress arises from atomic-level strain, and how stress can induce structural transformations at the nanoscale.

New algorithms for the optimization of alloy nanoparticles (nanoalloys) are presented. The new algorithms are based on the concept of multiple basin‐hopping walkers running in parallel, each with its own specialized task—the flying walker, exploring the energy landscape at high temperatures to sample different geometric structures, and the landing and hiking walkers mainly refining the optimization of chemical ordering at low temperatures. These algorithms are referred to as flying‐landing (FL) and flying‐landing‐hiking (FLH). The algorithms are tested against several benchmarks (AuCu and AuRh clusters of 400 atoms and PtNi clusters of 38 and 55 atoms). In all cases, both FL and FLH are shown to perform very well compared to previous results in the literature. In addition, the algorithms are applied to the optimization of larger AgCu nanoparticles, with sizes up to 4000 atoms, in order to establish the behavior of the mixing energy and to compare full global optimization of shape and chemical ordering with optimization of chemical ordering alone at a fixed shape. In general, the results show that the simultaneous optimization of shape and chemical ordering is necessary in many cases, and that the FLH approach is especially efficient for that purpose. [ABSTRACT FROM AUTHOR]

Due to their optical properties (localized surface plasmon resonance, LSPR), colloidally dispersed metal nanoparticles are well suited for selective heating by high‐energy laser radiation above their melting point without being limited by the boiling point of the solvent, which represents an excellent complement to wet‐chemical nanoparticle synthesis. By combining wet‐chemical synthesis and postsynthesis laser treatment, the advantages of both methods can be used to specifically control the properties of nanoparticles. Especially in the colloidal synthesis of nanoalloys consisting of two or more metals with different redox potentials, wet‐chemical synthesis quickly reaches its limits in terms of composition control and homogeneity. For this reason, the direct synthesis path is divided into two parts to take the strengths of both methods. After preparing Au–Cu hetero nanoparticles by wet‐chemical synthesis, nanoalloys with previous adjusted composition can be formed by postsynthesis laser treatment. The formation of these nanoalloys can be followed by different characterization methods, such as transmission electron microscopy (TEM), where the fusion of both metal domains and the formation of spherical and homogeneous Au–Cu nanoparticles can be observed. Moreover, the alloy formation can be followed by different shifts of X‐ray diffraction (XRD) reflections and LSPR maxima depending on the composition. [ABSTRACT FROM AUTHOR]

This article mainly explores the structural and electronic properties of Pt11X2 (X = Au, Cu, Ru and Rh) cluster using Density Function Theory—DFT. The plane wave function of DFT as well as Exchange–Correlation functionals have been used to calculate the isomers of doped Pt11X2 clusters, primarily to classify the stable atomic cluster structures. The main task comprises of the study on keeping two dopants at nearby/adjacent and opposite positions. Furthermore, the Pt11X2 cluster stability is examined using total energy calculations. The analysis of Pt11X2 cluster indicates that nearby doping positions of Pt11Ru2 show the more stable structure than Pt11Au2, Pt11Cu2 and Pt11Rh2 clusters. In addition to that the Bader's theory of charge analysis of Pt11X2 cluster indicates charge distribution within the cluster structure varies from − 0.43 to + 0.24 e. In general, this article explains the importance of keeping the atoms at strategic places of the nearby and opposite positions of Pt11X2 cluster to find the lowest energy structure. [ABSTRACT FROM AUTHOR]

Copper homometallic and copper-rich heterometallic nanoclusters with some Cu(0) character are reviewed. Their structure and stability are discussed in terms of their number of “free” electrons. In many aspects, this structural chemistry differs from that of their silver or copper homologs. Whereas the two-electron species are by far the most numerous, only one eight-electron species is known, but more electron-rich nanoclusters have also been reported. Owing to the relatively recent development of this chemistry, it is likely that more electron-rich species will be reported in the future.

The possibility of using ruthenium in the composition of palladium–rhodium catalysts used to neutralize the exhaust gases of vehicles with gasoline engines was investigated. The thermolysis of a supported precursor in oxidizing and reducing atmospheres led to the formation of samples with different initial catalytic activity. The stability of trimetallic systems was compared under conditions of prompt thermal aging with that of reference samples of similar chemical composition but obtained by mechanical mixing of monometallic catalysts. The results obtained allowed us to conclude that the alloy nanoparticles were more stable, and the thermolysis of the precursor in a reducing atmosphere contributed to a higher initial activity of the catalyst in the oxidation of CO. According to the X-ray photoelectron spectroscopy data, the high thermal stability of trimetallic catalysts was due to a constant ratio between metals on the support surface in the course of the catalytic reaction. [ABSTRACT FROM AUTHOR]

Throughout history, objects with fivefold symmetry have been a popular topic of interest for artists, philosophers, and scientists. This may be because fivefold symmetry is very conspicuous in nature. In the case of crystals, fivefold rotational symmetry is mathematically forbidden, and macroscopic crystals exhibiting fivefold symmetry have never been shown to exist. Nevertheless, in the nanoworld, nanoparticles are often found with decahedral and icosahedral shapes that have an overall pseudo‐fivefold symmetry. These structures are observed at many length scales, from 1 nm up to 1 µm. In this review, several reasons for the stability of fivefold nanoparticles are discussed. These include the formation of twin boundaries, surface reconstruction faceting, and other factors. [ABSTRACT FROM AUTHOR]

The development of new heterogeneous Pt-containing catalysts has retained its relevance over the past decades. The present paper describes the method to produce metal–carbon composites, Pt1−xNix/CNF, with an adjustable Pt/Ni ratio. The composites represent Pt1−xNix (x = 0.0–1.0) nanoparticles embedded within a structure of carbon nanofibers (CNF). The synthesis of the composites is based on a spontaneous disintegration of Pt1−xNix alloys in an ethylene-containing atmosphere with the formation of CNF. The initial Pt1−xNix alloys were prepared by thermolysis of multicomponent precursors. They possess a porous structure formed by fragments of 100–200 nm. As was shown by X-ray diffraction analysis, the crystal structure of the alloys containing 0–30 and 60–100 at.% Ni corresponds to a fcc lattice based on platinum (Fm-3m), while the Pt0.50Ni0.50 sample is an intermetallic compound with the tetragonal structure (P4/mmm). The impact of the Ni content in the Pt1−xNix samples on their activity in ethylene decomposition was studied as well. As was revealed, the efficiency of Pt1−xNix alloys in this process increases with the rise of Ni concentration. The composite samples were examined in an electrochemical hydrogen evolution reaction. The synthesized Pt1-xNix/CNF composites demonstrated superior activity if compared with the Pt/Vulcan commercial catalyst. [ABSTRACT FROM AUTHOR]

The selective hydrogenation of biomass‐derived levulinic acid (LA) to γ‐valerolactone (GVL) is one of pivotal reactions in many of the biorefinery schemes for the production of value‐added chemicals and biofuels. Herein, we have fabricated carbon‐supported bimetallic NiCo catalysts based on the metal–organic framework (MOF) material via a pyrolysis method. The as‐obtained Ni1Co1 bimetallic catalyst outperforms monometallic counterparts in the catalytic performance of LA‐to‐GVL, with a nearly full conversion of LA and a GVL yield of 95.2%, in particular with an excellent catalyst stability up to seven consecutive runs at 160°C and 4 MPa H2. Based on a combined characterization study by employing advanced techniques, for example, extended x‐ray absorption fine structure (EXAFS), high‐angle annular dark‐field scanning transmission electron microscopy (HADDF‐STEM), and electron paramagnetic resonance (EPR), we reveal that the enhanced catalytic performance, in particular the excellent stability, could be attributed to the formation of the bimetallic alloys, which efficiently alleviates the metal leaching and sintering during catalysis. [ABSTRACT FROM AUTHOR]

The article reveals for the first time the features of nanoparticle morphology, phase compositions, and their changes when heating FePt and CoPt nanoalloys. Nanoparticles were obtained by co-reduction of precursor solution mixtures with hydrazine hydrate. The features were found by a complex of methods of X-ray diffraction (in situ XRD and X-ray scattering), TEM HR, and cyclic voltammetry. In addition, adsorbometry results were obtained, and the stability of different nanocluster structures was calculated by the molecular dynamics method. There were only FCC solid solutions in the X-ray patterns of the FePt and CoPt nanoalloys. According to XRD, in the case of nanoparticle synthesis with Fe and Co content less than 10 at. %, the composition of solid solutions was close to or practically equal to the composition of the as-synthesized nanoparticles quantified by inductively coupled plasma optical emission spectrometry. For systems synthesis with Fe and Co content greater than the above, the solubility limits (SLs) of Fe and Co in Pt were set 11.4 ± 0.7 at. % and 17.5 ± 0.6 at. %, respectively. Therefore, there were non-registered XRD extra-phases (XRNDPh-1) in the systems when CFe,Co ≥ SL. This statement was supported by the results of TEM HR and X-ray scattering: the smallest nanocrystals (1–2 nm) and amorphous particles were found, which qualitatively agreed with the sorbometry and SAXS results. Molecular dynamics calculations of stability for FePt and CoPt alloys claimed the structures of the most stable phase corresponded to phase diagrams (A1 and L12). Specific peculiarities of the morphology and compositions of the solid solutions of nanoalloys were established: structural blockiness (domain) and composition heterogeneity, namely, platinum enrichment of internal (deep) layers and homogenization of the nanoalloy compositions at relatively low temperatures (130–200 °C). The suggested model of the formation of nanoalloys during the synthesis, qualitatively, was compliant with the results of electrochemical deposition of FePt films on the surface of various electrodes. When nanocrystals of solid solutions (C(Fe, Co) < SL) were heated above specific temperatures, there were phase transformations with the formation of two-phase regions, with solid solutions enriched with platinum or iron (non-registered XRD phase XRNDPh-2). The newly formed phase was most likely intermetallic compounds, FePt3, CoPt3. As a result of the study, the model was developed, taking into account the nanoscale of the particles: XRDPh (A1, FeaPt1−a) → XRDPh (A1, Fem×a−xPtm−m×a+x) + XRNDPh-2 (Fen×a+yPtn−n×a−y) (here, m + n = 1, m ≤ 1, n ≤ 1).

Nanomedicine relies on the exploitation of nanoscale constructs for therapeutic and diagnostic functions. Gold and gold–iron alloy nanoparticles (NPs) are two examples of nanomaterials with favorable features for use in nanomedicine. While gold NPs have been studied extensively in the last decades, they are not biodegradable. Nonetheless, biodegradation was recently observed in gold alloys with iron obtained using laser ablation in liquid (LAL). Hence, there is a significant interest in the study of the biological effects of gold and gold–iron alloy nanoparticles, starting from their tolerability and cytotoxicity. In this study, these two classes of NPs, obtained via LAL and coated with biocompatible polymers such as polyethylene glycol, were investigated in terms of their cytotoxicity in fibroblasts, prostate cancer cells (PC3) and embryonic kidney cells (HEK). We also explored the effects of different synthetic procedures, stabilizing additives, and the possible mechanisms behind cell mortality such as the formation of reactive oxygen species (ROS) or ferroptosis. NPs larger than 200 nm were associated with lower cell tolerability. The most tolerable formulations were pure PEG-Au NPs, followed by PEG-Au–Fe NPs with a hydrodynamic size < 50 nm, which displayed a toxicity of only 20% in fibroblasts after 72 h of incubation. In addition, tumor cells and highly proliferating HEK cells are more sensitive to the NPs than fibroblasts. However, a protective effect of catalase was found for cells incubated with PEG-Au–Fe NPs, indicating an important role of hydrogen peroxide in alloy NP interactions with cells. These results are crucial for directing future synthetic efforts for the realization of biocompatible Au NPs and biodegradable and cytocompatible Au–Fe alloy NPs. Moreover, the correlation of the cytocompatibility of NPs with ROS and ferroptosis in cells is of general interest and applicability to other types of nanomaterials.

Using seleno-compounds and telluric compounds is a practical approach for developing solutions against drug-resistant bacterial infections and malignancies. It will accelerate the search for novel treatments or adjuvants for existing therapies. Selenium and tellurium nanospheres can be produced by lactic acid bacteria. The bacteria can differentiate the selenium and tellurium when the medium contains both selenite and tellurite. Therefore, our question in this study was the following: are they making alloys from the selenium and tellurium and what will be the composition, color, and shape of the nanoparticles? We used a simple microbial synthesis to produce nanoselenium, nanotellurium, and their alloys from sodium selenite and sodium tellurite using Lactobacillus casei. This bacterium produced red spherical amorphous elemental selenium nanospheres with a diameter of 206 ± 33 nm from selenite and amorphous black nanorods with a length of 176 ± 32 nm and a cross-section of 62 ± 13 nm from tellurite. If the initial medium contains a mixture of selenite and tellurite, the resulting nanoparticles will contain selenium and tellurium in the same ratios in the alloy as in the medium. This proves that Lactobacillus casei cannot distinguish between selenite and tellurite. The shape of the nanoparticles varies from spherical to rod-shaped, depending on the ratio of selenium and tellurium. The color of nanomaterials ranges from red to black, depending on the percentage of selenium and tellurium. These nanomaterials could be good candidates in the pharmaceutical industry due to their antipathogenic and anticarcinogenic properties.

Multi‐element nanoparticles (NPs) consisting of five or more elements have been increasingly studied in the past five years. Their emergence is taking materials science one step further because they exhibit superior properties to those of conventional NPs in a range of respects, including catalysis. This Review focuses on the recent progress in multi‐element NPs regarding synthesis, especially with regard to chemical synthesis, characterization, and properties. We begin with a brief introduction of multi‐element NPs and an overview of their synthesis methods. Then, we present representative examples of multi‐element alloy NPs and ceramic NPs, including oxide NPs prepared by chemical syntheses. This Review intends to provide useful insights into the chemical methods that are used to synthesize multi‐element NPs, and includes a discussion on the possibilities arising from their use in new functional materials. [ABSTRACT FROM AUTHOR]

Discharge in liquid is a promising technique to produce nanomaterials by electrode erosion. Although its feasibility was demonstrated in many conditions, the production of nanoalloys by in-liquid discharges remains a challenge. Here, we show that spark discharge in liquid cyclohexane that is in contact with conductive solution, made of a combination of Ni-nitrate and/or Fe-nitrate and/or Co-nitrate, is suitable to produce nanoalloys (<10 nm) of Ni-Fe, Ni-Co, Co-Fe, and Ni-Co-Fe. The nanoparticles are synthesized by the reduction of metal ions during discharge, and they are individually embedded in C-matrix; this latter originates from the decomposition of cyclohexane. The results open novel ways to produce a wide spectrum of nanoalloys; they are needed for many applications, such as in catalysis, plasmonic, and energy conversion. [ABSTRACT FROM AUTHOR]

This article mainly intended to investigate the structural and electronic properties of Pt13 cluster with two atoms doped M (Ag, Ir, and Pd) within the framework of the density functional theory. The plane wave and DoS methods along with spin-polarized exchange–correlation functionals have been used to study the isomers of Pt11M2-doped clusters mainly to categorize the lowest energy structures. This work is mainly to analyze the advantage/impact on two atoms doping over the single-atom doping. This work also discusses study on placing two doping atoms at adjacent and opposite positions. In addition to this, the atom clusters stability has been examined based on the total energy and binding energy calculations. The comparative analysis of Pt11M2 isomer reveals that adjacent doping positions show the lowest energy than opposite positions. Further study of Bader charge analysis of Pt11M2 cluster indicates charge transfer within the atomic structure ranging from − 1.37 to + 1.17e. Overall, this article outlines the significance of placing the atoms at strategic places of the adjacent site and opposite site of Pt11M2 cluster as well as in obtaining the lowest energy structure. [ABSTRACT FROM AUTHOR]

Binary alloys A B composed of ferromagnetic metals A (Fe, Co, Ni) and the late 4 d − 5 d noble metals B (Rh, Pd, Ag, Ir, Pt, Au) have been investigated using density functional theory with the generalized gradient approximation to understand the role of magnetism in the stability and the order–disorder transition which has an impact on their physicochemical properties, their applications and their possible implementation as precursors of high-entropy alloys. The enthalpy of formation related to the stability demonstrates that all the alloys are more stable in the ferromagnetic phase than in the nonmagnetic phase. The transition from ordered to disordered phases is quantified using a descriptor which is the standard deviation of the energy spectrum of a set of small nanoalloys with random atomic configurations. The study highlights the fact that the entropy-related descriptor, which is a quantity in determining the formation of a disordered phase as a solid solution or an ordered phase is highly dependent on the atomic environment. Despite the fact that the overall variation of this descriptor is supposed to be unpredictable, there is a noticeable trend showing that the environment-dependent ferromagnetism contributes to a chemical order in alloys and nanoalloys and that this order depends on the atomic radius of the species considered. The results indicate that species with small atomic radii, such as nickel, rhodium or iridium are more likely to form solid solutions than species with larger atomic radii and with more delocalized orbitals. [Display omitted] • The stability of the alloys is mainly due to the ferromagnetism and the spin magnetic moment depends on the charge in the d-band and charge transfers. • The entropy descriptor shows that the ferromagnetic state favors ordered phases at a finite temperature over disordered phases. • The entropy descriptor depends on the atomic environment and shows that species with a small atomic radius are more likely to form solid solutions. [ABSTRACT FROM AUTHOR]

Utilizing plant extracts in the green synthesis of bimetallic nanoalloys receives more attention due to its eco-friendly, cheap, single-step, easy-handling method, producing highly active and biocompatible nanoalloys. Therefore, the aqueous extract of ginger rhizome was used to form bimetallic gold/silver (Au/Ag) nanoalloys. There were 37.3 mg.g−1 of total soluble carbs, 0.75 mg.g−1 of proteins, and 0.03 mg.g−1 of phenolic compounds quantified in ginger rhizome. The production of BAu/Ag-NPs relies on these components. The as-formed BAu/Ag-NPs were characterized using UV–Vis spectroscopy. The results showed that the peak surface plasmon resonance (SPR) occurred between 440 and 545 nm. The existence of several functional groups involved in the reduction and stability of the generated nanoalloys was shown by Fourier-transform infrared (FT-IR). The nanoalloys, with an average size of 49.1 ± 16.2 nm, were observed to be spherical using transmission electron microscopy (TEM). Energy-dispersive X-ray (EDX) indicated that the synthesized nanoalloy mainly consisted of Au and Ag ions, which made up (31.2 % and 47.1 %) and (45.9 % and 28.6 %) of the sample's atomic and weight percentages, respectively. The crystallography of the nanoalloys was confirmed using XRD analysis. When examined for their capacity to suppress viral replication, the synthesized nanoalloys showed remarkable results, with 78.2 % inhibition against HAV and 69.6 % against Cox-B4. In addition, the anticancer activity of nanoalloys against oral epithelial cells (OEC), MCF7 adenocarcinoma cells, and HepG2 hepatocarcinoma cells was investigated using the MTT assay method. While the nanoalloys exhibited moderate toxicity towards normal OEC (IC50: 502.5 ± 2.8 g.mL−1), they showed substantial cytotoxicity towards cancer cells, MCF7 and HepG2, with IC50 values of 212.6 ± 4.4 and 117.9 ± 6.6 µg.mL−1, respectively. According to these data, BAu/Ag nanoalloys show potential as antiviral and anticancer drugs that selectively kill cancer cells. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries present a promising solution to high‐energy and low‐cost energy storage. However, the conversion‐type redox mechanism determines the poor fulfillment of battery chemistry in terms of reversibility and kinetics. Herein, a flower‐like graphene microassembly decorated with finely‐dispersed Ni2Co nanoalloy (Ni2Co@rGO) is developed as advanced host matrix for Li–S batteries. Combining computational, physicochemical, and electrochemical studies, Ni2Co nanoalloys are unveiled synergizing strong adsorbability against polysulfide shuttling and excellent catalytic activity for sulfur conversions. Meanwhile, the sophisticated architecture renders facile electron/ion transport and highly‐exposed active interfaces. These virtues collaboratively contribute to fast and durable sulfur electrochemistry with a minimum capacity degradation of 0.034% per cycle over 500 cycles and a rate capability up to 5 C. Besides, the implementation of Ni2Co@rGO as the anode matrix tames the Li redox behavior benefiting from the enhanced lithiophilicity and reduced local current density. As such, the full cell configuration pairing S‐Ni2Co@rGO cathode and Li‐Ni2Co@rGO anode realizes a favorable areal capacity of 4.53 mAh cm−2 under high sulfur loading (4.0 mg cm−2) and limited electrolyte (E/S = 6.0 mL g−1). This work offers an elaborate bi‐service matrix engineering to simultaneously improve the conversion reversibility and kinetics for superior Li–S batteries. [ABSTRACT FROM AUTHOR]

Although the theoretical electrocatalytic activity of rhenium (Re) for the hydrogen evolution reaction is comparable to that of platinum, the experimental performance of reported rhenium-based electrocatalysts remains unsatisfactory. Herein, we report a highly efficient and stable electrocatalyst composed of rhenium and cobalt (Co) nanoalloy embedded in nitrogen-doped carbon film (Re 3 Co 2 @NCF). The Re 3 Co 2 @NCF electrocatalyst exhibited remarkable hydrogen evolution performance, with an overpotential as low as 30 ± 3 mV to reach a current density of 10 mA cm -2 . In addition, the Re 3 Co 2 @NCF demonstrated exceptional stability over several days at a current density of 150 mA cm -2 . Theoretical calculations revealed that alloying cobalt with rhenium altered the electronic structure of the metals, causing partial oxidation of the superficial metal atoms. This modification provided a balance for various intermediates' adsorption and desorption, thereby boosting the intrinsic activity of rhenium for hydrogen evolution reaction. This work improves the electrocatalytic performance of rhenium to its theoretical activity, suggesting a promising future for rhenium-based electrocatalysts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The development of peroxidase mimic nanocatalysts is relevant for oxidation reactions in biosensing, environmental monitoring and green chemical processes. Several nanomaterials have been proposed as peroxidase mimic, the majority of which consists of noble metals and oxide nanoparticles (NPs). Yet, there is still limited information about how the change in the composition influences their catalytic activity. Here, the peroxidase mimic behaviour of gold NPs is compared to a traditional nanoalloy as Au-Ag and to the Au-Fe and the Au-Co nanoalloys, which were not tested before as oxidation catalysis. Since the alloys of gold with iron and cobalt are thermodynamically unstable, laser ablation in liquid (LAL) is exploited for the synthesis of these NPs. Using LAL, no chemical stabilizers or capping agents are present on the NPs surface, allowing the evaluation of the oxidation behaviour as a function of the alloy composition. The results point to the importance of surface gold atoms in the catalytic process, but also indicate the possibility of obtaining active nanocatalysts with a lower content of Au by alloying it with iron, which is earth-abundant, non-toxic and low cost. Overall, Au nanoalloys are worth consideration as a more sustainable alternative to pure Au nanocatalysts for oxidation reactions., (© 2024 Wiley‐VCH GmbH.)

This study reports the application of FeCuNi nano-alloy doped TiO2 synthesized via the sol-gel method as an antibacterial with a sterilization rate greater than 95% under ultra-violet (UV) irradiation. The performance was characterized using X-ray diffraction (XRD), thermal analysis (TG-DTA), scanning electron microscope (SEM-EDX), and transmission electron microscope (TEM). The results showed that the sterilization process of FeCuNi–TiO2 in cell suspension of Escherichia coli, Staphylococcus aureus and Bacillus subtilis increased the effectiveness of UV irradiation at wavelength (λ) ≥ 385 nm after 120 min. The optimum growth inhibition of FeCuNi–TiO2 was observed in the concentrations 1.5 g/L of E. coli, 1.5 g/L of S. aureus and 2.0 g/L of B. subtilis. The highest antimicrobial efficiency of FeCuNi–TiO2 powder was provided by a particle size of 16.8 nm, surface area of 70.98 m2/g. The increased antimicrobial activity in multiplied-three doped ions was related to the increase of illumination energy of UV absorption in the photo-catalyst process. The inhibition mechanism reaction of the three species of bacteria cell affects the lipid peroxidation process at the microbe cell’s wall. This was indicated by the formation of malondialdehyde (MDA). Lipid oxidation was based on the reaction of 2-thiobarbituric acid (TBARS) as an indicator of primary and secondary oxidation.

In this paper, the melting behaviors of Rh–Ag–Au nanoalloys are investigated with MD simulation. For Rh–Ag–Au nanoalloys, icosahedron structure was considered. The local optimizations of Rh–Ag–Au nanoalloys were carried out with the BH algorithm. The interatomic interactions were modeled with the Gupta potential. The local optimization results of Rh–Ag–Au nanoalloys show that Au and Ag atoms prefer to locate on the surface, and Rh atoms prefer to locate in the inner shells. The bond order parameter result is compatible with the excess energy analysis. It is noted that structures with more Ag–Au bonds are more energetically stable. Caloric curve, heat capacity, Lindemann index, and RMSD methods were used for estimating the melting temperatures of Rh–Ag–Au nanoalloys. According to the simulation results, melting temperatures depend on the composition. Also, it is discovered that nanoalloys are generally melting in two stages. Surface melting of the third shell is occupied by Ag and Au atoms, and then homogeneous melting of the inner shells is occupied by Rh atoms. It is found that the difference between surface melting temperatures and homogeneous melting temperatures in Ag-poor compositions is more significant than that of Ag-rich nanoalloys. In addition, the melting temperatures of the nanoalloys are found to be increased as the size of nanoalloys increases. [ABSTRACT FROM AUTHOR]

Adsorption of molecular hydrogen on the surface of catalytic metal nanoparticles and its dissociation in atomic hydrogen are processes of interest in many chemical technologies. As in other chemical reactions, alloying can improve the efficiency of the catalysts. By focusing on Co 6 , Co 5 Ag, Co 3 Ag 3 and CoAg 5 , we explore the effect of changing the relative concentration of the two components in small Co m Ag n clusters, a peculiar nanoalloy because Co and Ag do not form bulk solid alloys. Molecular hydrogen adsorbs preferentially on the Co atoms, and the binding is mainly due to the electrical polarization of the charges of adsorbate and host. The preference for Co sites and the trend in the strength of the H 2 -cluster binding are explained by the combination of two effects characterizing the host environment. One of these is geometric, arising from the degree of exposure of the host atom: the lower the atomic coordination of the host atom, the stronger its bonding with H 2. The second effect, newly identified, reveals the importance of the chemical nature of the host atom environment: host Co atoms having both Co and Ag neighbors maintain their capacity to bind hydrogen more intact than those with only Co neighbors. The alloy nanoclusters catalyze the dissociation of adsorbed H 2 by building up quite small activation barriers. After dissociation, the H atoms occupy bridge positions between Co atoms (between Co and Ag in CoAg 5). H 2 adsorption and dissociation may trigger structural transformations of the cluster. The work shows that the adsorption and dissociation properties of H 2 can be tuned by varying the relative composition of the two atomic species in the nanoalloy. • Alloying Co clusters with Ag improves their catalytic activity towards hydrogen. • Hydrogen adsorbs preferentially on the Co atoms of the CoAg nanoalloys. • Adsorption sites are determined by host coordination and chemical environment. • Activation barriers for H 2 dissociation on CoAg nanoalloys are small. [ABSTRACT FROM AUTHOR]

• Ternary Pd-Rh-Ru alloy was prepared by the thermolysis of a single-source precursor. • The atmosphere of thermolysis was demonstrated to be a crucial factor. • The activity in CO oxidation was used to examine the alumina-supported catalysts. • The catalytic performance was studied in comparison with bimetallic Pd-Rh catalyst. • Partial substitution of Rh with Ru increased both the activity and thermal stability. In the present work, alumina-supported trimetallic Pd-Rh-Ru catalysts were synthesized and studied in comparison with the bimetallic Pd-Rh reference sample. The alloy nanoparticles were formed on the surface of the alumina support by thermolysis of the complex salts [Rh(NH 3) 5 Cl][Pd(NO 2) 4 ] and [Rh(NH 3) 5 Cl] 0.5 [Ru(NH 3) 5 Cl] 0.5 [Pd(NO 2) 4 ], preliminary deposited via an incipient wet impregnation method. The influence of the conditions of the thermolysis process on the phase composition of the final products and the size of the trimetallic particles was established. Thus, nanoscale trimetallic (Rh-Ru-Pd) alloy particles of a given composition were obtained. The catalytic performance of the alumina-supported samples was examined in a CO oxidation reaction under prompt thermal aging conditions. It was ascertained that the addition of ruthenium only improves both the initial activity and thermal stability of the catalytic system. The state of each metal in the alloy nanoparticles was characterized by diffuse reflectance UV–vis spectroscopy and X-ray photoelectron spectroscopy. [Display omitted] [ABSTRACT FROM AUTHOR]

Using density functional theory, we determine the magnetic properties and the size effects of iron, cobalt and nickel nanoparticles and their alloys with platinum. Some weak oscillations of the spin magnetic moment are found due to the relaxation acting on the distances between the shells of the nanoparticles. The magnetic moment of the pristine nanoparticles depends mainly on the coordination. In the nanoalloys, due to a localization resulting from the variation of the atomic potential by assembling two different species, the magnetic moment of the nanoalloys is less dependent on the coordination and is more uniformly distributed at the surface. • A descriptor shows that the energy of the nanoalloys is closer to the energy of bulk materials compared to pristine metal nanoparticles. • The relaxation effects tend to produce a weak oscillation of the spin magnetic moment especially for large size nanoparticles. • The spin magnetic moment does not depend much on the coordination in the nanoalloys because of a localization due to the variation of the atomic potential by assembling two different species. • The significant difference between the atomic potentials of iron and platinum causes an uniform distribution of the spin magnetic moment at the surface of the FePt nanoalloys compared to the other nanoalloys. [ABSTRACT FROM AUTHOR]

The development of new heterogeneous Pt-containing catalysts has retained its relevance over the past decades. The present paper describes the method to produce metal–carbon composites, Pt1−xNix/CNF, with an adjustable Pt/Ni ratio. The composites represent Pt1−xNix (x = 0.0–1.0) nanoparticles embedded within a structure of carbon nanofibers (CNF). The synthesis of the composites is based on a spontaneous disintegration of Pt1−xNix alloys in an ethylene-containing atmosphere with the formation of CNF. The initial Pt1−xNix alloys were prepared by thermolysis of multicomponent precursors. They possess a porous structure formed by fragments of 100–200 nm. As was shown by X-ray diffraction analysis, the crystal structure of the alloys containing 0–30 and 60–100 at.% Ni corresponds to a fcc lattice based on platinum (Fm-3m), while the Pt0.50Ni0.50 sample is an intermetallic compound with the tetragonal structure (P4/mmm). The impact of the Ni content in the Pt1−xNix samples on their activity in ethylene decomposition was studied as well. As was revealed, the efficiency of Pt1−xNix alloys in this process increases with the rise of Ni concentration. The composite samples were examined in an electrochemical hydrogen evolution reaction. The synthesized Pt1-xNix/CNF composites demonstrated superior activity if compared with the Pt/Vulcan commercial catalyst.

We report results of structural studies of multicomponent compounds, double complex salts, used as predecessors of nanoalloys of immiscible metals in Rh–Pd, Rh–Pd–Pt, Au–Pt, Au–Ir, Au–Rh, Au–Ir–Rh, Ru–Pd systems. Structural features of the crystals of these complexes are discussed in terms of preparing novel multicomponent precursors to fabricate nanoalloys of immiscible metals. Thermal behavior of these compounds responsible for the formation of metastable nanoalloys are discussed. It is shown that directed synthesis of single-phase nanoalloys is possible in the systems of immiscible metals. Mechanisms of nanoalloy formation in a reducing atmosphere are described. The data on chemical and phase compositions of polymetallic powders, the products of thermal degradation of considered compounds, are reported. [ABSTRACT FROM AUTHOR]

Well distributed Pd/Cu bimetallic nanoalloy supported on acid-modified sepiolite (ASEP) was prepared via a solvothermal process. The resulting system, Pd/Cu@ASEP, was characterized using spectroscopic data such as FT-IR, XRD, TEM and ICP-AES. The morphology characterization revealed that the crystalline bimetallic particles were dispersed on ASEP as nanoalloys with diameters ranged from 25 to 30 nm. This system was successfully used for ligand-free Mizoroki-Heck coupling in the presence of air, under mild conditions. This method has advantages compared to other systems, such as short reaction times, high yields, facile catalyst and easy separation and reusability of the catalyst. The catalyst was compatible with a variety of aryl and heteraryl iodides, which provides favorable products with good to high yields. Aryl and heteraryl bromides could also be activated for the Mizoroki-Heck reaction using Pd/Cu@ASEP catalyst, with good to moderate yields. [ABSTRACT FROM AUTHOR]

Exemplifying on two bimetallic nanoparticles Cu — Pt and Au — Ag, the internal structure and external surface has been investigated in the process of dealloying. Equiatomic compositions with the total number of atoms Ntot = 3000 are considered. In the dealloying process half of both the copper and silver atoms were removed. The Monte Carlo method within the Metropolis scheme is used as a simulation method. The interatomic interaction was described by the tight-binding potential. As it was expected, the selective corrosion leads to the fact that the surface layer of the particle is enriched with one of the components atoms. However, the particle core retains the structure of the binary nanoalloy. We also found that as a result of the selective corrosion, a defective structure of the nanoparticle is formed. Accordingly, we assume that it is these defects (mainly vacancies) that lead to the porous structure of larger binary nanoparticles observed in experiments on the dealloying. A change in the specific surface area per unit volume or weight affects the adsorption and catalytic properties, as well as the corrosion resistance of bimetallic nanoparticles.