Weakening hydroxyl intermediate binding achieves efficient oxygen reduction reaction for electrochemical cell sensing.

Transition metal/dECM hydrogel complexation for large-sized cell spheroid.

An In-rich Cu-In intermetallic compound (IMC), CuIn2, was accessed through an electrochemical nonequilibrium pathway and obtained as bulk Cu2In core/CuIn2 shell nanoparticles. CuIn2 is thermodynamically metastable in the Cu-In binary phase diagram and has previously been observed only at Cu/In interfaces in sputtered thin films. Here, electrochemical reduction of a mixed metal oxide precursor (Cu2In2O5) under aqueous CO2 reduction conditions enables the formation of a metastable CuIn2 shell encapsulating a Cu2In core. The resulting biphasic IMC particles exhibit characteristic CO2 reduction selectivity with strongly suppressed competing H2 evolution. Density functional theory calculations suggested that CO adsorption at Cu bridge sites on the In-rich CuIn2(121) surface competitively inhibits H adsorption, which may contribute to the suppressed H2 evolution. This work demonstrates a nonequilibrium electrochemical route for accessing metastable IMC phase through oxygen-elimination-induced restructuring of a mixed metal oxide precursor.

For the goal of mitigating energy scarcity via hydrogen production from water electrolysis, the high performance, low cost transition-metal-based catalysts are essential to be designed and manufactured. In this study, we prepare chromium-doped nickel cobalt phosphide/nickel sulfide (Cr-NiCoP/Ni3S2) heterostructured hollow nanowires on conductive nickel foam through a two-step hydrothermal method coupled with low temperature phosphorization procedure. Benefiting from the remarkable electron transport capability inherent in transition metal compounds, the large specific surface area afforded by distinctive hollow nanowire architecture, and the interfacial synergistic effect of heterostructure, the as-obtained catalyst delivers low overpotentials of 67 mV for HER and 243 mV for OER at a current density of 10 mA cm-2 in alkaline electrolyte. Additionally, in an electrolytic system where the Cr-NiCoP/Ni3S2 acts as bifunctional anode and cathode materials, the 10 mA cm-2 current density can be achieved at a cell voltage of 1.47 V with good stability. This catalyst demonstrates better performance than the majority of reported transition metal based bifunction substances. The work described in this paper not only develops a new class of catalytic materials integrating application potential and expense advantage but also provides important strategic support for the fabrication and optimization of nonprecious metal electrocatalysts.

The microstructural characteristics of solder alloys critically determine their mechanical performance and reliability in high precision electronic applications. These characteristics including phase distribution, grain size, and intermetallic compound (IMC) formation govern the alloy’s response to thermal and mechanical stresses. Precise control of IMCs such as Cu6Sn5 and Ag3Sn, along with uniform fine grains, enhances toughness, creep resistance, and reduces fracture susceptibility. In this study, the effect of low copper additions (0.2–1 wt %) on the (96.5- x) Sn − 3.5Ag − xCu alloy was systematically investigated through a combination of XRD and SEM analyses. The results reveal a clear dependence of crystallite size, dislocation density, and IMC distribution on copper content and identify the optimal Cu concentration for stabilizing the β -Sn phase while improving mechanical properties. These findings provide a detailed understanding of microstructural evolution under low-Cu alloying, offering insights not addressed in previous studies.

In this work, the effect of Zn content on the interfacial microstructure and the thickness of the intermetallic compound (IMC) layer formed at the contact interface between Sn–xZn solder alloys and the C1990HP substrate alloy was investigated. Sn–1Zn, Sn–5Zn, and Sn–9Zn solder alloys were soldered onto a C1990HP substrate at 270 °C and held for durations of 0.5 h and 2 h. The results show that Zn content strongly influences the morphology and growth behavior of the intermetallic layer at the interface. At lower Zn contents, the intermetallic layer is relatively thick and exhibits cracking and fragmentation, resulting in the dispersion of small intermetallic particles into the solder alloy. As the Zn content increases, the intermetallic layer becomes more stable. EDS analysis reveals the presence of Cu–Zn-rich regions at the interface, indicating that Zn plays a dominant role in the reaction between the Sn–xZn solder alloy and the C1990HP substrate. Increasing the holding time from 0.5 h to 2 h leads to an increase in the overall thickness of the IMC layer. These results demonstrate that Zn addition and holding time are the key factors controlling the interfacial reaction behavior and the overall growth of the IMC layer in the Sn–xZn/C1990HP system.

First-principles calculations of the structural parameters, elastic constants, mechanical moduli, Debye temperature, and density of states (DOS) of cubic CsCl-type (B2) XAu (X = Er, Tm) rare-earth intermetallic compounds under hydrostatic compression up to 20 GPa have been performed. The calculations were carried out within the framework of density functional theory (DFT) using the pseudopotential plane-wave (PP-PW) method and the local density approximation (LDA). The calculated elastic constants indicate that both ErAu and TmAu with the CsCl-type (B2) phase satisfy the Born mechanical stability criteria at equilibrium and under pressure up to 20 GPa for ErAu and up to about 19 GPa for TmAu. The zero-pressure structural parameters, elastic constants, and mechanical moduli are generally in good agreement with previously reported theoretical data. The calculated zero-pressure Young's modulus values are 96.61 GPa for ErAu and 73.94 GPa for TmAu, while the corresponding Debye temperatures are 193K and 167K, respectively. The obtained results reveal that hydrostatic pressure enhances the stiffness of both compounds, as reflected by the general increase in the elastic constants, acoustic wave velocities, and Debye temperature. Both ErAu and TmAu exhibit ductile behavior according to Pugh's ratio and show noticeable elastic anisotropy. The electronic-structure analysis confirms the metallic character of both compounds, while additional GGA + U calculations indicate that the localized 4f states are sensitive to the Hubbard correction without changing their metallic nature. The pressure-dependent elastic constants and related mechanical and thermodynamic properties of XAu (X = Er, Tm) intermetallic compounds have not been previously reported; therefore, the present results provide useful predictions and reference data for future theoretical and experimental studies.

Site isolation is an effective strategy for achieving high selectivity for acetylene semihydrogenation, yet often at the cost of reduced activity. Moreover, most of the site isolation approaches involve single-atom catalysts (SACs), less is known about the active site ensemble that can behave even superior to SACs in both activity and selectivity. Herein, by decoration of partially reduced GaOx on the Pd particles in Pd/Al2O3 and followed by in situ treatment in reaction gas, we are able to construct isolated Pd3 sites and identify the structure by using in situ CO-DRIFTS and DFT calculations. Reaction tests for acetylene semihydrogenation under simulated industrial feed gas conditions show that the isolated Pd3 sites offer ∼99% ethylene selectivity at acetylene conversion of 95% at very mild reaction conditions (50 °C and 1 bar), with a turnover frequency of 13.5-fold that of Pd2Ga intermetallic compound, outperforming most of the state-of-the-art Pd-based catalysts. The combined TPD experiments and theoretical calculations reveal that the partially reduced GaOx on the Pd surface not only isolates and stabilizes the Pd3 geometry but also alters the electronic properties of Pd via electron transfer from Ga to Pd atoms, thereby enhancing acetylene adsorption while weakening ethylene adsorption, leading to greatly increased activity and selectivity. This work opens up a distinct avenue from the prevalent SAC strategy toward site-isolation, highlighting the great potential of manipulating the active site ensemble in overcoming the activity-selectivity trade-off in selective hydrogenation reactions.

ABSTRACT In the event of an animal disease outbreak such as African Swine Fever (ASF), many thousands of swine may succumb to the disease or need to be euthanized to contain the outbreak. Swine mortalities will need to be properly and quickly disposed of to limit spread of the disease and mitigate environmental impacts. On-site carcass disposal options such as composting and burial eliminate the need to transport the carcasses over roadways, thus reducing biosecurity concerns. Another on-site animal carcass disposal option being considered is the use of mobile incinerators/cremators. Field tests were conducted in 2024 to evaluate two different sized mobile incinerators for their carcass disposal potential. The tests evaluated the incinerators’ throughput, fuel usage, and ash generation. In addition, sampling and analysis of the bottom ash and air pollutant emissions from the incinerators were performed. Several air pollutants were measured at the stack, including particulate matter, dioxins/furans, nitrogen oxides, sulfur dioxide, metals, and others. The average charge rates of swine carcasses to the large and small incinerators during testing was 359 and 59 kg per hr, respectively. The highest mass emission rate of any pollutant from the large incinerator was 1.08 kg/hr (for nitrogen oxides), and for the smaller incinerator, emissions were at de minimis levels. Similarly, analyses of the bottom ash found that all metal and organic compound analytes were below the laboratory’s reporting limit. These results from the evaluation of the incinerators may inform officials on their use in the event ASF reaches their country. Implications: This work shows the promise of using mobile incinerators to process swine carcasses in the event of a foreign animal disease outbreak such as African Swine Fever. The research presents for the first time data on throughput, air emissions and bottom ash from the cremation of swine mortalities using portable incineration units. This work may inform officials in their selection of options for the disposition of animal mortalities in a large-scale animal disease event.

Interstitial electronic states, commonly found in F-centers and electrides, have garnered significant attention in materials discovery, and applications spanning catalysis and electronics. Here, we demonstrate that active-metal-rich intermetallics serve as a platform for forming diverse cationic cages that accommodate distinct interstitial electrons. This arises from two key factors: (1) the high atomic density of active metals, promoting their aggregation to form cages; and (2) the high valence electron density, facilitating electron confinement in cage voids. We examine 10 metal-rich RE-T-Al/Mg (RE = rare earth, T = transition metal) ternary compounds as examples. Density functional theory (DFT) calculations reveal that these compounds exhibit electride characteristics, featuring tiered interstitial electrons at distinct Wyckoff sites and energy levels. Detailed analyses identify two types of interstitial electrons: those in RE-rich cages, with band centers at -1.25 eV< E-EF < 0eV, ∼1 e-/site, and negative hydrogen binding energies, exhibiting anionic-like behavior; and those in Al cages, with band centers at E-EF < -1.8eV, ∼2 e-/site, and positive hydrogen binding energies, displaying covalent-like behavior. Our results provide a systematic insight into interstitial electrons in RE-T-Al/Mg ternary compounds, potentially offering a guideline for designing intermetallic compounds with tailored interstitial electronic states.

First-principles study of intermetallic compounds in Al–Si alloys: electronic structure and thermal transport properties

Nanozymes for caries and periodontitis: Mechanisms, therapeutic applications, and future perspectives.

Single crystals of a Eu-based Zintl compound, Eu9Zn4.5As9, were synthesized by a flux method and characterized by single-crystal X-ray diffraction, magnetic measurements, heat capacity, and electrical transport. Eu9Zn4.5As9 crystallizes in an orthorhombic structure (space group Pnma) composed of a highly complex Zn-As polyanionic framework featuring multiple types of Zn coordination and partially occupied Zn sites. The presence of partially occupied Zn sites leads to deviations from ideal Zintl electron counting, resulting in metallic electrical transport. Magnetic susceptibility, isothermal magnetization, and heat capacity measurements reveal multiple magnetic transitions at low temperatures, including the development of a short-range ferromagnetic order below ∼15 K, a long-range antiferromagnetic transition at 11.3 K, and a further transition into a canted antiferromagnetic state at 6.8 K. In addition, a negative magnetoresistance of up to -40% is observed at low temperatures, reflecting a strong coupling between the Eu2+ moments and the itinerant charge carriers. These results demonstrate that Eu9Zn4.5As9 is a metallic Zintl compound with a structurally complex polyanionic framework and rich magnetic behaviors.

ConspectusThe term "intermetallic" refers to a new metallic structure generated by the formation of intermetallic bonds of two or more different constituting metals. In solid-state synthesis, a very high temperature and a long duration are required to address the challenge of breaking the stable homometallic bonds and generating heterometallic bonds with the periodic diffusion of all metals forming the new compound. In nanoparticle synthesis via solution-phase methods, different atoms experience competition between the rate of reduction and diffusion, which majorly controls the formation of ordered and disordered compounds between two different metals. Intermetallic compounds (IMs) provide a unique combination of thermodynamic stability, long-range atomic ordering, heteroatomic surfaces, and electronically tunable frameworks, making them highly active and versatile for electrocatalysis. In this context, Pd2Ge stands out as a chemically intriguing intermetallic template for generating highly stable and efficient electrocatalysts. In this Account, we summarize the multiyear research of our group establishing Pd2Ge as a model platform for understanding how elemental diffusion, site-specific substitution, active interface generation, and electronic structure tuning can transform a single ordered intermetallic into a multifunctional electrocatalyst family. We showed that the solution-phase synthesis of Pd2Ge nanoparticles is achievable through careful control of the reduction kinetics and diffusion pathways, despite the significant reduction potential mismatch between Pd2+ and Ge4+. Our approach achieves the simultaneous coreduction of Pd2+ and Ge4+ precursors, effectively suppressing GeO2 formation and enabling the clean evolution of the Pd2Ge phase. After overcoming the challenge of binary intermetallic synthesis, a major challenge in intermetallic chemistry is the controlled incorporation of a third metal without disrupting the long-range order; this is governed by the reduction potential, atomic-size matching, orbital-overlap, site-preference energetics, and diffusion barriers. We demonstrate that the Pd sites in Pd2Ge can accommodate Ni, Co, Pt, and Cu through element-specific diffusion and reduction kinetics, enabling substitution up to a variable diffusion limit while preserving the ordered framework. This provides an atomic-level example for experimentally probing multimetal diffusion and lattice accommodation in a stable intermetallic matrix. Site-selective substitution has been proven by powder X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and density functional theory (DFT). The exact charge transfer mechanism after different element substitution has been evidenced via XPS and XAS. Our group has explored the electrochemical properties of different metal-substituted Pd2Ge in the ethanol oxidation reaction (EOR), oxygen reduction reaction (ORR), formaldehyde oxidation reaction (FAOR), and oxygen evolution reaction (OER). The exact reaction mechanism and the active site determination of this intermetallic for these reactions have been exhaustively determined via different operando spectroscopic and analytical techniques and DFT calculations. This Account gives a broad overview and a guideline about the intermetallic generation and full exploration of a stable intermetallic and how fine-tuning of the intermetallic gives rise to different electrochemical superiorities. Collectively, this Account presents the first integrated exploration of Pd2Ge as a robust and electronically programmable intermetallic, showing how kinetic control, thermodynamic driving forces, and site-selective multimetal diffusion can be leveraged to design high-performance electrocatalysts across diverse reaction environments.

Recently, transition-metal-doped molybdenum disulfide (TM-MoS2) has become a frontier in gas sensor research. However, high-quality TM-MoS2 with both outstanding sensitivity and high selectivity remains scarce, as discovering new TM-MoS2 is impeded by the insufficiency of robust and rapid predictions of gas adsorption properties of the huge amounts of possible candidates. First-principles calculations provide an effective method to investigate electronic properties and offer a critical reference for experimental preparation, while the high consumption of computational time hinders their broad exploration of all possible material systems. Herein, the present work proposes a novel first-principles machine learning (FPML) approach to directly predict gas sensing trend of TM-MoS2 and efficiently discover new superior material systems from over 870 datasets. The accuracy and reliability of first-principles calculations for analyzing gas detection performance are demonstrated by experimental results first. By establishing a series of novel feature descriptors, including adsorption energy, band gaps, work function, and charge transfer, requiring low computation cost, the ML model is constructed by high accuracy (R-square value of 0.95) and high reliability (mean absolute error value of 0.13) for adsorption energy, requiring a reduced amount of training data. We discovered more than 42 promising unreported candidates by the ML model. Some of the systems exhibit higher performance than the reported materials. This work supplies an efficient and effective approach to discover gas detection trends of different two-dimensional metal compounds and other nanomaterials, which can expedite the rational design of the best novel gas sensor for various applications.

Intermetallic compounds exhibit long-range atomic ordering that endows them with physicochemical properties distinct from those of elemental metals and disordered alloys. Extending ordered intermetallics into ultrathin, freestanding geometries is of both fundamental and technological interest, yet it remains challenging because the high temperatures required for chemical ordering exceed the thermal stability of conventional sacrificial templates. Here, we introduce water-etchable aluminate oxides as lattice-matched, thermally robust sacrificial templates for the epitaxial growth and nondestructive release of intermetallic nanomembranes. Using Pt3Sn as a model system, we realize millimeter-scale freestanding membranes that preserve long-range chemical order and crystallographic orientation after being released. These nanomembranes maintain structural integrity and mechanical robustness during transfer and under mechanical loading, demonstrating their compatibility with flexible device architectures. Low-temperature magnetotransport measurements further reveal the preservation of quantum interference and multiband transport behaviors. This oxide template strategy establishes a generalizable synthetic pathway toward freestanding intermetallic nanomembranes and other ultrathin metal systems.

The interplay between localized magnetic moments and conduction electrons gives rise to a rich quantum phase diagram that underpins a wide range of exotic quantum phenomena. Within this framework, the mixed-valence regime where charge and spin fluctuations are entangled represents a crucial frontier for discovering novel quantum phenomena. However, such behavior has so far been largely confined to bulk intermetallic compounds containing rare-earth or actinide elements. Herein, we report the observation and precise tuning of the mixed valence regime in stable, pure organic Blatter-type radicals synthesized on a Au(111) surface. Using scanning tunneling microscopy and spectroscopy, we identify a characteristic asymmetric double-peak spectral line shape, in which the splitting of the resonance peaks arises from the hybridization of many-body states, while the asymmetry is intrinsic to the mixed-valence regime. Theoretical simulations based on an effective quasiparticle Hamiltonian well reproduce the experimental findings, validating this line shape as a spectroscopic fingerprint of mixed valence states. Furthermore, by engineering the local adsorption geometry, molecular configuration, and supramolecular assembly, we demonstrate in situ crossover between a Kondo-like state and a mixed-valence state in Blatter radical dimers on Au(111). This work establishes purely organic radicals as a new system for accessing the mixed-valence regime and its crossover with the Kondo regime, providing a well-defined and tunable chemical platform for exploring emergent quantum phenomena and their underlying physical mechanism at the single-molecule level.

Defect engineering boosts CC bond cleavage for highly efficient ethylene glycol electrooxidation on Pd2Pb3Zn4 intermetallic compound.

First-principles study on the electronic, thermodynamic, and optical properties of the metal compounds XPd(X=Fe, Ru) and XPd3(X=Co, Sn, Fe)

The global fight against malaria is currently hindered by the rapid emergence and spread of multi-drug-resistant Plasmodium falciparum strains. This growing resistance has compromised the efficacy of frontline treatments and has led to the disease continuing to claim thousands of lives each year. Consequently, a new effective and non-toxic anti-malarial drug is urgently needed. In this context, metal-NHC (N-heterocyclic carbene) complexes have diverse physicochemical properties that could enhance biological activity and lead to the development of a new drug to combat malaria. On this regard, this study examined the biological activity of two metal-NHC complexes and their NHC precursor in two strains of the parasite, Plasmodium (3D7 and FCR-3), with specific targets. The synthesis of all metal-NHC complexes was carried out under nitrogen atmosphere using Schlenk techniques. We studied the biological activity of two metal-NHC complexes and their NHC precursor in two Plasmodium strains (3D7 and FCR-3) and the selectivity index. Additionally, the possible interactions of these metal compounds with specific targets were evaluated. These targets included reactive oxygen species (ROS), albumin (BSA), Fe(III) PPIX, and β-hematin. The evaluation also included lipophilicity and ADMET properties. These properties were evaluated through diverse physical and spectroscopic methods. The IC50 values of the NHC precursor (L) and the two metal-NHC complexes (1 and 2) were similar in P. falciparum chloroquine-sensitive and -resistant strains. They showed a higher selectivity index than chloroquine and do not cause hemolysis in red blood cells. Additionally, the compounds have a dose-dependent effect on the progression of the P. falciparum erythrocytic cycle, resulting in the accumulation of ring and trophozoite forms at high concentrations in the FCR-3 strain. These compounds may alter the pH of acidic organelles in the cytosol of the parasite, such as the digestive vacuole and the accessory vacuoles. Compounds L, 1 and 2 are capable to generate reactive oxygen species (ROS). Preliminary studies reported in this paper suggest that the two metal-NHC complexes 1 and 2 interact with targets such as the inhibition of β-hematin and the production of reactive oxygen species (ROS). They also have lipophilic and physicochemical profiles that correlate with their antiplasmodial efficacy. Both complexes exhibit moderate activity, indicating potential for further evaluation. A plausible explanation is that this behavior arises from the nature of both the ligand and the metal center. Accordingly, these initial findings provide a basis for the further exploration of new antimalarial compounds.