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Equal‐period modulated metal/ceramic multilayers have shown promise in enhancing the toughness of ceramic thin films. However, this toughness enhancement typically comes at the sacrifice of hardness, limiting their potential applications. To tackle this issue, this study designed and fabricated two gradient‐structured multilayer variations using Ta/TaB2: one with a higher ceramic layer fraction near the surface (M2) and the other with a converse structure (M3). A conventional equal modulation period Ta/TaB2 multilayer film (M1) served as a reference. M2 exhibited superior performance, with a 30% hardness increase and significant toughness enhancement compared to M1. Conversely, M3 experienced failure due to excessive thermal stress from its unique gradient structure. Finite element simulations revealed that M2's structure could alleviate in‐plane stress and enhance loading uniformity, thus enhancing the film's toughness. These findings suggest that a well‐designed gradient structure holds promise for concurrently improving the hardness and toughness of metal/ceramic multilayer films. [ABSTRACT FROM AUTHOR]

The oxide layer formed by ultra‐high melt point oxides (ZrO2, HfO2) and SiO2 glassy melt is the key to the application of traditional thermal structural materials in extremely high‐temperature environment. However, the negative effect of ZrO2 and HfO2 phase transitions on the stability of oxide layer and rapid volatilization of low viscosity SiO2 melt limit its application in aerospace. In this study, the ablation behavior of Cf/(CrZrHfNbTa)C‒SiC high‐entropy composite was explored systematically via an air plasma ablation test, under a heat flux of 5 MW/m2 at temperatures up to 2450°C. The composite presents an outstanding ablation resistance, with linear and mass ablation rates of 0.9 µm/s and 1.82 mg/s, respectively. This impressive ablation resistance is attributed to the highly stable oxide protective layer formed in situ on the ablation surface, which comprises a solid skeleton of (Zr, Hf)6(Nb, Ta)2O17 combined with spherical particles and SiO2 glassy melt. The irregular particles provide a solid skeleton in the oxides protective layer, which increased stability of the oxide layer. Moreover, the spherical particles have a crystal structure similar to that of Ta2O5 and are uniformly distributed in SiO2 glassy melt, which hinder the flow of SiO2 glassy melt and enhance its viscosity to a certain degree. And it reduces the volatilization of SiO2. In summary, the stable oxide layer was formed by irregular particles oxide and the SiO2 glassy melt with certain viscosity, thereby resulting in the impressive ablation resistance of the composite. This study fills a gap in ablation research on the (CrZrHfNbTa)C system. [ABSTRACT FROM AUTHOR]

Discovering a competent charge transport layer promoting charge separation in photoelectrodes is a perpetual pursuit in photoelectrochemical (PEC) water splitting to achieve high solar‐to‐hydrogen (STH) conversion efficiency. Here, a conjugated polythiophene framework (CPF‐TTB) on Ta3N5 is elaborately electropolymerized, substantiating the hole transport behavior in their heterojunction. Tailored band structures of the CPF‐TTB/Ta3N5 reinforce the separation of photogenerated carriers, elevating a fill factor of the photoanode modified with a cocatalyst. The enhanced hole extraction enables the NiFeOx/CPF‐TTB/Ta3N5/TiN photoanode to generate a remarkable water oxidation photocurrent density of 9.12 mA cm−2 at 1.23 V versus the reversible hydrogen electrode. A tandem device combining the photoanode with a perovskite/Si solar cell implements an unbiased solar water splitting with a STH conversion efficiency of 6.26% under parallel illumination mode. This study provides novel strategies in interface engineering for metal nitride‐based photoelectrodes, suggesting a promise of the organic–inorganic hybrid photoelectrode for high‐efficiency PEC water splitting. [ABSTRACT FROM AUTHOR]

The topological and morphological changes of the (001) surface of single‐crystal (La0.3Sr0.7)(Al0.65Ta0.35)O3 during treatment with high‐purity deionized water (DI) have been investigated by atomic force microscopy and scanning transmission electron microscopy (STEM). Etching by DI treatment at room temperature proceeded mainly in anisotropic etching mode, resulting in rectangular etch pits with {001} inner surfaces forming in the surface. The dominant etching mode changed from anisotropic to isotropic with increasing DI‐treatment temperature, and the lowest surface roughness occurred for DI treatment at 50°C for 60 min. Direct observation of the atomic structure of the surface by STEM showed that the etched surface was the B‐site‐terminated (001) surface after anisotropic etching at 50°C for 60 min, in which the B‐site‐terminated atomic layer was found to maintain the B‐site ordered structure existing in the crystal. This is because DI treatment, which does not require high‐temperature heat treatment of the substrate, suppresses element diffusion, sublimation, and formation of point defects on and in the vicinity of the surface. [ABSTRACT FROM AUTHOR]

Phase change materials have issues in the automotive industry and in‐memory computing due to their limited thermal stability and high power consumption. Consequently, numerous studies are conducted to enhance the performance of these materials. Uncertainty persists regarding the effects and mechanisms of various doping on the parent material. In this study, four metallic doping elements are selected, and their effects on Sb2Te3 are meticulously analyzed through experiments and ab initio calculations. The thermal stability of Sb2Te3 has been somewhat enhanced by doping these four elements, with Ta doping having the most impact. According to the ab initio molecular dynamics, this improvement results from the tetrahedral centered In and the increased coordination numbers of Ta, Ti, and Sc. Sc located at the center of the octahedron can accelerate the crystallization process. Ta, in particular, exerts the greatest influence on the migration rates of Sb and Te, resulting in the slowest grain growth rate. Simultaneously, it maximizes the delay in the transition from the cubic phase to the hexagonal phase. These features are beneficial for reducing power consumption. The elucidation of the distinct effects of doping elements sets the stage for phase change memory to adapt to various application scenarios. [ABSTRACT FROM AUTHOR]

Ta1−xAlxN thin films with 5, 15, and 40 at.% Al addition were co‐deposited by reactive magnetron sputtering and characterized by Rutherford backscattering spectroscopy (RBS), grazing angle X‐ray diffraction (GAXRD), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), nanohardness, and oxidation tests. GAXRD and XPS analyses showed, regardless of the % Al added, the non‐existence of ternary nitride Ta1−xAlxN, but always as individual binary nitrides, TaN and AlN. Sample TaAlN_15 obtained the highest hardness and H3/E2 values, possibly due to the AlN grains presence, which were efficient in distorting the TaN lattice. All samples failed oxidation tests at 873 K, showing that the Al addition was not efficient in improving this property for tantalum aluminum nitride thin films. [ABSTRACT FROM AUTHOR]

Radiation detection is being revolutionized by integrating photonic elements into scintillators. In this study, a scalable and cost‐effective method is proposed to achieve tuneable emission enhancement across the visible spectrum by colloidal self‐assembly of photonic crystals on scintillator surfaces. This concept is demonstrated for Eu3+/Tb3+‐doped Gd and Ta oxides. Widely available and affordable colloidal nanospheres of SiO2 or polymethyl methacrylate are self‐assembled on these scintillators. The size of the nanospheres is carefully optimized to match the desired emission lines of Eu3+/Tb3+. The result is homogeneous and closely‐packed structures with clear photonic bandgap in the visible range. Under X‐ray excitation, the scintillators covered with the photonic layers exhibit enhanced light extraction in the direction perpendicular to the surface, compared to isotropic emission in the bare scintillator. Such scintillation directionality, when optically matched with a proper detector, will result in higher efficiency of the overall detection system. Moreover, X‐ray imaging demonstrates an enhancement of 25% in system resolution of the scintillator supplemented with the photonic layer compared to unmodified scintillators. The proposed method is scintillator‐ and nanosphere‐agnostic, thus offering a promising versatile approach for directing the scintillation light toward a photodetector and increasing detection system performance, including high‐resolution imaging applications. [ABSTRACT FROM AUTHOR]

Molten oxide electrolysis is a promising pathway to decarbonize primary metal production. The oxide electrolyte is less hazardous and eco‐toxic than halides (molten salt electrolysis) and, with the use of renewably generated electricity and an inert anode, oxygen is produced as a by‐product instead of CO2. Building fundamental understanding of electrolytic operating windows requires starting with simple chemistries. Here we investigate a simplified binary oxide system as an electrolyte for titanium oxide reduction to metal. The TiO2−Na2O binary system forms a eutectic, reducing the liquidus temperature over a wide composition range. FactSage 8.1 predictions suggested Ti reduction would become favorable over Na reduction for compositions greater than 0.49 mole fraction TiO2. The prediction was validated by the detection of metallic Ti after electrolysis experiments. However, the reduction efficiency was too low (0.24±0.08 % at −0.1 V vs Ti reference electrode) for the TiO2−Na2O system to be a viable industrial electrolyte for Ti production. Scoping for other binary oxide systems was performed for electrolytic production of two critical metals, tantalum and neodymium. Based on TiO2−Na2O system's predicted behavior, candidate binary oxide systems were identified that contained congruently melting line compounds flanked by eutectic reactions from the ACerS‐NIST Phase Equilibria diagrams database. [ABSTRACT FROM AUTHOR]

The photoelectrochemical performance of Ta3N5 photoanodes is strongly impacted by the presence of shallow and deep defects within the bandgap. However, the role of such states in defining stability under operational conditions is not well understood. Here, a highly controllable synthesis approach is used to create homogenous Ta3N5 thin films with tailored defect concentrations to establish the relationship between atomic‐scale point defects and macroscale stability. Reduced oxygen contents increase long‐range structural order but lead to high concentrations of deep‐level states, while higher oxygen contents result in reduced structural order but beneficially passivate deep‐level defects. Despite the different defect properties, the synthesized photoelectrodes degrade similarly under water oxidation conditions due to the formation of a surface oxide layer that blocks interfacial hole injection and accelerates charge recombination. In contrast, under ferrocyanide oxidation conditions, it is found that Ta3N5 films with high oxygen concentrations exhibit long‐term stability, whereas those possessing lower oxygen contents and higher deep‐level defect concentrations rapidly degrade. These results indicate that deep‐level defects result in rapid trapping of photocarriers and surface oxidation but that shallow oxygen donors can be introduced into Ta3N5 to enable kinetic stabilization of the interface. [ABSTRACT FROM AUTHOR]

Extensive efforts have been devoted to investigate the distribution of dopants in ceramics. However, one critical question remained barely explored, which is the redistribution of dopants between amorphous and crystalline phases during fast sintering of ceramics. Here we address this gap by observing the redistribution of five selected dopants (Y, Ce, Yb, Hf, and Ta) in ZrO2–SiO2 nanoceramics during sintering. We designed two groups of experiments: In group one, dual‐phase amorphous particles were sintered with multicomponent crystalline ones. The former particles were ZrO2–SiO2 glass, whereas the latter ones consisted of ZrO2 solid‐solution nanocrystallites (SSNCs) embedded in an oxide glass containing Zr, Si, Y, Ce, Hf, Yb, and Ta. In group two, dual‐phase crystalline particles were sintered with multicomponent amorphous ones. The former particles were composed of ZrO2 nanocrystallites (NCs) embedded in an amorphous SiO2 matrix, whereas the latter ones were oxide glass containing Zr, Si, Y, Ce, Hf, Yb, and Ta. Redistribution of the dopants from the glass to ZrO2 NCs occurred in the two groups, that is, the five dopants migrated from the glass matrix into the ZrO2 NCs, forming ZrO2 SSNCs. The redistribution of the dopants not only increased the configuration entropy of the ZrO2 NCs but also benefited the network structure integrity of SiO2 glass. The dopant redistribution process was driven by the minimization of the studied material's free energy. The reported results are important for understanding the redistribution behaviors of dopants and are expected to provide new insights to design new ceramics via the multielement co‐doping strategy. [ABSTRACT FROM AUTHOR]

Garnet‐type Li7La3Zr2O12 electrolytes have garnered significant attention as promising solid‐state electrolyte candidates in all‐solid‐state lithium batteries (ASSLBs). However, its susceptibility to forming Li2CO3 upon atmospheric exposure leads to performance degradation, limiting its application. This study introduces a co‐doping strategy of Mg and Ta to enhance the properties of garnet electrolytes. Pure cubic Mg and Ta‐doped LLZO electrolytes are successfully synthesized using the solid‐state reaction method. Experimental results, coupled with density functional theory (DFT) calculation, reveal that Mg2+ doping occurs primarily at the La site (24c). This substitution, given the substantial disparity in ionic radii between Mg2+ and La3+, effectively narrows the transport bottleneck for Li‐ions, resulting in a decreased ionic conductivity and an increased activation energy. Li6.6La2.8Mg0.2Zr1.4Ta0.6O12 exhibits a relative density of ≈92.6%, demonstrating outstanding performance with a room temperature ionic conductivity of 4.31 × 10−4 S cm−1 and low electronic conductivity of 2.48 × 10−8 S cm−1. Notably, after 4 months of atmospheric exposure, its ionic conductivity decreased to ≈78% of the initial value, attributable to Li2CO3 formation. Furthermore, the material demonstrated exceptional long‐term cycle stability over 1000 h at a current density of 0.1 mA cm−2 at 25 °C, indicating effective suppression of Li dendrite formation. [ABSTRACT FROM AUTHOR]

Surface modification is an important approach to improve osseointegration of the endosseous implants, however it is still desirable to develop a facile yet efficient coating strategy. Herein, a metal–phenolic network (MPN) is proposed as a multifunctional nanocoating on titanium (Ti) implants for enhanced osseointegration through early immunomodulation. With tannic acid (TA) and Sr2+ self‐assembled on Ti substrates, the MPN coatings provided a bioactive interface, which can facilitate the initial adhesion and recruitment of bone marrow mesenchymal stem cells (BMSCs) and polarize macrophage toward M2 phenotype. Furthermore, the TA‐Sr coatings accelerated the osteogenic differentiation of BMSCs. In vivo evaluations further confirmed the enhanced osseointegration of TA‐Sr modified implants via generating a favorable osteoimmune microenvironment. In general, these results suggest that TA‐Sr MPN nanocoating is a promising strategy for achieving better and faster osseointegration of bone implants, which can be easily utilized in future clinical applications. [ABSTRACT FROM AUTHOR]

The Ta/CoFeB/Pt/MgO/HfO2 system is investigated, whose magnetic anisotropy can be controlled through magneto‐ionic gating, using both ionic liquid and solid state gating, via a non‐oxidative mechanism combining reversible and irreversible gating effects. Analysis of X‐ray absorption spectroscopy at the Co and Fe edges reveals no indications of oxidation after gating, while a reversible change at the oxygen K edge suggests the involvement of oxygen species in the magneto‐ionic process. In addition, X‐ray diffraction measurements reveal that gating can irreversibly increase the crystalline volume of MgO, through an increase in the MgO/Mg(OH)2 ratio. This is in line with measurements in solid state devices showing that in a series of 150 gating cycles a reversible effect combines with a progressive increase in the strength of the perpendicular magnetic anisotropy contribution that saturates after extensive cycling. Consequently, the observed gate‐induced changes in magnetic anisotropy can be attributed to the combined effects of Mg(OH)2 dehydration into MgO (irreversible) and most likely a gentle reordering of oxygen species at the CoFeB interface (reversible) leading to a non‐oxidative magneto‐ionic mechanism. This study provides valuable insights into the underlying mechanisms governing the complex magneto‐ionic phenomena, including the coexistence of both reversible and irreversible effects, and a pathway to voltage‐control of crystalline order in spintronics materials. [ABSTRACT FROM AUTHOR]

Core–shell architectures provide great opportunities to improve catalytic activity, but achieving nanoparticle stability under electrochemical cycling remains challenging. Herein, core–shell nanoparticles comprising atomically thin Pt shells over earth‐abundant TaC cores are synthesized and used as highly durable electrocatalysts for the methanol oxidation reaction (MOR) and the oxygen reduction reaction (ORR) needed to drive direct methanol fuel cells (DMFCs). Characterization data show that a thin oxidic passivation layer protects the TaC core from undergoing dissolution in the fuel cell‐relevant potential range, enabling the use of partially covered Pt/TaC core–shell nanoparticles for MOR and ORR with high stability and enhanced catalytic performance. Specifically, at the anode the surface‐oxidized TaC further enhances MOR activity compared to conventional Pt nanoparticles. At the cathode, the Pt/TaC catalyst feature increases tolerance to methanol crossover. These results show unique synergistic advantages of the core–shell particles and open opportunities to tailor catalytic properties for electrocatalytic reactions. [ABSTRACT FROM AUTHOR]

Currently, previous studies of low‐temperature sintering of high‐entropy carbide ceramics (HECCs) have followed the traditional approach to use the low‐melting‐point metals, such as Co, Ni, and so forth, as sintering additives. However, metallic binders can cause adverse impacts on hardness of HECCs. This study reported an innovation processing method for low‐temperature sintering of HECCs, which involved the use of various contents of CrN as sintering additive and spark plasma sintering at 1600°C to obtain dense HECCs. In comparison to the grain size of pure (Ti, Zr, Nb, Ta, Mo)C bulk sintered at 2000°C (3.29 ± 1.02 μm), the grain size of samples with the addition of 5–15 wt.% CrN sintered at 1600°C was significantly smaller, ranging from 0.32 to 0.48 μm. By using only 5 wt.% CrN, dense (Ti, Zr, Nb, Ta, Mo)C ceramics with a high hardness value of 26.73 ± 0.43 GPa could be obtained. Furthermore, increasing the amount of CrN to 15 wt.% resulted in a fracture toughness of 3.78 ± 0.10 MPa·m1/2. It is anticipated that the (Ti, Zr, Nb, Ta, Mo)C ceramic with an ideally combined hardness and toughness can be achieved at low sintering temperatures by the proper control of CrN content. [ABSTRACT FROM AUTHOR]

The effect of vacuum ultraviolet (VUV) radiation during ionized physical vapor deposition (IPVD) of tantalum barriers on various porous organosilicate glass low‐k SiCOH films is studied using advanced diagnostics and quantum chemical calculations. VUV photons break the Si–C bonds, releasing hydrocarbon radicals from the pore surfaces. These radicals, trapped in pores that are partially sealed by tantalum deposition, can either react with tantalum to form carbide‐like compounds, TaCx, or be redeposited in the pores as CHx polymers. This is evidenced by a decrease in CH3 groups that correlates with an increase in TaCx. The formation of TaCx poses a significant challenge in the back end of line (BEOL) technology when reducing the barrier thickness. [ABSTRACT FROM AUTHOR]

Eco-friendly ceramic capacitors gradually become an important section of pulsed power devices. However, the synchronous realization of ultra-high energy storage density (Wrec > 6 J/cm³) and efficiency (η > 90%) is difficult. Thus, a novel multiscale amelioration strategy in Na0.5Bi0.5TiO3-based ceramics is proposed to achieve ultra-high energy storage density and efficiency. The multiscale amelioration strategy for (Na0.5Bi0.47La0.03)0.94Ba0.06TiO3 (NBLBT) ceramic focuses on grain size, bandgap width, and dielectric relaxor behavior, which can be regulated by introducing Sr(Al0.5Nb0.25Ta0.25)O3 (SANT). On the one hand, the refined grain size and increased bandgap width are conducive to improving the breakdown strength. On the other hand, the optimized dielectric relaxation behavior is beneficial to suppress the remanent polarization. Accordingly, an ultrahigh Wrec = 6.89 J/cm³ and η = 90.1% are simultaneously achieved in 0.84NBLBT- 0.16SANT ceramic. In addition, the sample synchronously possesses excellent thermal and frequency stability (a variation within 5% in Wrec and η), transient discharge rate of t0.9 ~ 78.8 ns and a high-power density of PD ~ 114.5 MW/cm³. This study provides an effective strategy to further develop pulsed power devices. [ABSTRACT FROM AUTHOR]

Due to the huge composition space, composition screening is of great importance to the optimization of high‐entropy diborides (HEBs) with exceptional oxidation resistance. However, related studies are lacking. Here, a novel rapid, effective strategy to fully screen the compositions on the oxidation resistance of HEBs is proposed. Specifically, the synthesis of the equiatomic 1‐ to 9‐cation multicomponent diborides of the IVB, VB, and VIB groups in seconds via an ultrafast ultrahigh‐temperature synthesis technique is realized. Subsequently, combined with the thermogravimetric analysis and first‐principles calculations, the roles of incorporated elements are systematically explored. The results show that Zr, Cr, Ta, Nb, and W elements are the key to the improved oxidation resistance of HEBs, while Ti, Mo, and V elements are destructive. In particular, the positive roles of metal elements are mainly attributed to the partial dissolution of the generated metal oxides into the generated B2O3 glass, which can improve the viscosity of B2O3 and thus enhance its high‐temperature stability and reduce the oxygen diffusion rate, as confirmed by the first‐principles calculations. This study paves a way to rapidly screen the elements in HEBs, which can be a guide for further anti‐oxidation designs. [ABSTRACT FROM AUTHOR]

MXenes have gained significant attention, particularly Ti3C2Tz, as materials with favorable properties for energy storage and conversion applications. The overwhelming majority of electrochemical durability studies are based on durability in the hydrogen evolution window, well below the reversible hydrogen electrode where degradation via electrochemical oxidation is less relevant. Consequently, few strategies have been put forward to protect Ti3C2Tz at higher potentials and widen their applicability to electrochemical systems. Here, the electrochemical degradation of pristine Ti3C2Tz and tantalum (Ta)‐substituted (Ti0.95Ta0.05)3C2Tz is reported. X‐ray photoelectron spectroscopy and electron microscopy revealed that pristine and Ta‐doped MXene went through entirely different degradation mechanisms, and that these mechanisms are driven by electrochemical, rather than chemical effects. Density functional theory is used to explain the role of Ta doping with respect to the binding of oxygen and the formation of metal oxide phases. The influence of the degradation mechanism is observed by accelerated stress tests and anode reversal tests on a polymer electrolyte membrane fuel cell. Therefore, the substitution of titanium (Ti) with other oxyphilic metals in Ti3C2Tz may be an effective route to improve the durability of the otherwise fragile MXene phase. [ABSTRACT FROM AUTHOR]

Herein, the photoelectric properties of Ta‐doped β‐Ga2O3 are studied based on first‐principles density functional theory calculation. The effects of interstitial H and O vacancies on the properties of the system are also considered. The electronic structure, dielectric function, absorption spectrum, mobility, and conductivity of all the systems are studied and analyzed. The results show that Ta‐doped β‐Ga2O3 is an n‐type direct‐bandgap semiconductor. With the increase in Ta doping concentration, the dielectric constant, polarization ability, and charge binding ability of the system gradually increase, the bandgap gradually narrows, and the absorption spectra of systems redshift. The main absorption wavelengths of all systems are in the wavelength range of less than 300 nm. Therefore, Ta‐doped β‐Ga2O3 has an ultraviolet detection ability. The introduction of Ta is beneficial to improve the conductivity of the system. Interstitial H can improve the conductivity of the system. [ABSTRACT FROM AUTHOR]

A high-flux sub-micrometre focusing system was constructed using multilayer focusing mirrors in Kirkpatrick–Baez geometry for 100 keV X-rays. The focusing mirror system had a wide bandwidth of 5% and a high peak reflectivity of 74%. Performance was evaluated at the undulator beamline BL05XU of SPring-8, which produced an intense 100 keV X-ray beam with a bandwidth of 1%. When the light source was focused directly in both vertical and horizontal directions, the beam size was measured to be 0.32 mm (V) × 5.3 mm (H) with a flux of 1 × 1012 photons s-1. However, when a limited horizontal slit was used to form a secondary source, the focusing beam size decreased to 0.25 mm (V) × 0.26 mm (H) with a flux of 6 × 1010 photons s-1. The 200 nm line and space patterns of a Siemens star chart made of tantalum were clearly resolved by the absorption contrast of the focused beam. This 100 keV focusing system is applicable to various fields of nondestructive analyses with sub-micrometre resolutions. [ABSTRACT FROM AUTHOR]

BaTiO3‐based compounds are recognized as the most common dielectric material used in multilayer ceramic capacitors (MLCCs), among which, BaTiO3‐BiMeO3 is extensively investigated to improve the thermal stability and extend the service life of MLCCs, which are strongly dependent on the conductivity at high temperatures. Despite numerous efforts have been made, the mechanism of oxygen vacancy conduction, which makes the major contributions to the conduction mechanism of BaTiO3‐based compounds at high temperatures below 450°C, is still unclear. In this paper, BaTiO3, 0.88BaTiO3‐0.12Bi(Zn2/3Nb1/3)O3, 0.88BaTiO3‐0.12Bi(Mg2/3Nb1/3)O3, and 0.88BaTiO3‐0.12Bi(Mg2/3Ta1/3)O3 ceramics have been prepared by solid‐state reaction method, and their electrical and dielectric properties have been studied in detail. Meanwhile, first principles were applied to study the mechanisms of the increase of electrical resistivity and the decrease of dielectric loss. It is found that B‐site dopants (Zn, Mg, Nb, and Ta) are effective in reducing the conductivity by inhibiting the migration of oxygen vacancies, which is a kinetics process with an increase of energy barrier. Notably, the greater ability of Zn to inhibit oxygen vacancies migration is a combination of thermodynamics (a strong ability to trap oxygen vacancies) and kinetics (an effect of block the migrating defects in the lattice). This work reveals a new insight into the mechanism of oxygen vacancies migration in BaTiO3‐based perovskite compounds, which makes BaTiO3‐BiMeO3 prospective in designing efficient and durable medium‐temperature solid oxide capacitor devices. [ABSTRACT FROM AUTHOR]

Herein, the photoelectric properties of Ta‐doped β‐Ga2O3 are studied based on first‐principles density functional theory calculation. The effects of interstitial H and O vacancies on the properties of the system are also considered. The electronic structure, dielectric function, absorption spectrum, mobility, and conductivity of all the systems are studied and analyzed. The results show that Ta‐doped β‐Ga2O3 is an n‐type direct‐bandgap semiconductor. With the increase in Ta doping concentration, the dielectric constant, polarization ability, and charge binding ability of the system gradually increase, the bandgap gradually narrows, and the absorption spectra of systems redshift. The main absorption wavelengths of all systems are in the wavelength range of less than 300 nm. Therefore, Ta‐doped β‐Ga2O3 has an ultraviolet detection ability. The introduction of Ta is beneficial to improve the conductivity of the system. Interstitial H can improve the conductivity of the system. [ABSTRACT FROM AUTHOR]

As integrated circuits continue to shrink in size, the demand for high‐quality adhesive layers in copper Damascene interconnects has increased. However, tantalum (Ta) films, used as liners, prepared by atomic layer deposition (ALD) from metal halide precursors, are prone to corrosion and exhibit issues such as low film density and unstable performance. In this study, Ta films are successfully fabricated using a plasma‐enhanced ALD (PEALD) process with an organometallic precursor of Ta(NtBu)(NEt2)3 (TBTDET). The study of the growth conditions reveals that introducing 10% Ar in Ar‐H2 mixed gas leads to continuous high‐quality Ta films. The deposited Ta films are free of halogen impurities, which can avoid the detrimental impact on the stability of the Cu interconnects. Although the films contain some carbon and nitrogen impurities, they do not affect the film adhesive properties. Transmission electron microscopy shows that the Ta films are amorphous, and the amorphous Ta films exhibit superior barrier properties. Moreover, highly uniform Ta films can be conformally deposited into narrow interconnect structures using this PEALD process. These findings suggest that the Ta films prepared by the organometallic precursor can offer a promising solution to address the issues related to the halogen elements in the adhesive layer preparation. [ABSTRACT FROM AUTHOR]

Platinum is known as the best catalyst for the hydrogen evolution reaction (HER) but the scarcity and high cost of Pt limit its widespread applicability. Herein, the role of the underlying substrate on the HER activity of dispersed Pt atoms is uncovered. A direct current magnetron sputtering technique is utilized to deposit transition metal (TM) thin films of W, Ti, and Ta as underlying substrates for extremely low loading of Pt (<1.5 at%). The electrocatalytic performance of as‐synthesized samples for the HER is examined in both alkali and acidic media. The results show that despite the low loading of Pt, the Pt/TM catalysts produce hydrogen at a rate comparable to that of pristine bulk Pt. Pt/TM catalysts also display good stability with less than 5% decay in performance after 10 h of continuous HER operation. Based on the computational study, the excellent performance is attributed to the modified electronic properties of the Pt atoms, offering ideal binding energy for HER due to interaction with the underlying substrates. This work provides a robust and industry‐friendly route toward designing efficient catalytic systems for important electrochemical reactions such as HER and others. [ABSTRACT FROM AUTHOR]

Mantle metasomatism, which affects the geochemical and lithological properties of the Earth, is crucial to the evolution and modification of the Earth's interior. Variations in chemical proxy of metasomatism, including high‐field strength elements (HFSE, e.g., Zr‐Ti isotopes and isovalent Zr‐Hf), have been commonly utilized as a tool to unravel the processes associated with the evolution of the Earth. However, the impact of mantle metasomatism by diverse agents on the Zr isotopic compositions of metasomatized mantle remains poorly understood. Here we carried out high‐precision double‐spike δ94/90Zr measurements for a suite of basalts, which were derived from the mantle sources metasomatized by typical metasomatic agents of fluid, silicate melt and carbonate melt originating from the deep mantle or recycled crustal materials. Mantle metasomatism results in lithological diversities within the mantle, ranging from hybridized peridotites to pyroxenite/eclogite and carbonated eclogite, which can significantly fractionate the isovalent HFSEs. However, our data show that these basalts have primitive mantle‐like δ94ZrNIST values (−0.033–0.043 ‰), regardless of their superchondritic Zr/Hf. The primitive mantle‐like δ94ZrNIST, irrelevant to any proxy of metasomatism (e.g., Sr‐Nd isotopes, Zr/Hf and La/Sm), indicate that mantle metasomatism and subsequence melting produce no measurable Zr isotopic variations in metasomatized mantle‐derived basalts. The δ94ZrNIST of basalts thus can be representative of the mean metasomatized mantle compositions. Combined with previously reported komatiites and oceanic basalts, we show that the Earth's mantle displays consistent δ94ZrNIST (−0.013 ± 0.053 ‰), even if it has a secular dynamic evolution with the interaction between Earth's exterior and interior. Plain Language Summary: Mantle metasomatism has a significant impact on the geochemical and lithological properties of the Earth's interior. The chemical variations, including the high‐field strength elements (HFSE), caused by this process, could provide key insights into such modification. However, the variation of Zr isotopes during mantle metasomatism remains enigmatic. Here, we analyzed the Zr isotopes of fresh basalts derived from mantle sources metasomatized by diverse metasomatic agents. We find that although mantle metasomatism leads to the substantial fractionation of Zr (Nb) from Hf (Ta), no measurable Zr isotopic variation occurs for metasomatized mantle‐derived melts, as reflected by the homogeneous and primitive mantle‐like Zr isotopic compositions of different samples. Combining our findings with previous data, we conclude that the Earth's mantle, from large‐scale and secular perspectives, maintains a consistent Zr isotopic composition, although the Earth underwent complex and dynamic evolution. Key Points: A first comprehensive investigation of Zr isotopes of mantle metasomatized by diverse agents of fluid, silicate melt and carbonate meltBasalts derived from metasomatized mantle show variable radiogenic isotopes and trace element patterns, but limited Zr isotope variationThe Earth's mantle exhibits consistent δ94Zr, despite its secular dynamic evolution with interaction between Earth's exterior and interior [ABSTRACT FROM AUTHOR]

Lamprophyres typically appear in hydrothermal gold deposits. The relationship between lamprophyres and gold deposits is investigated widely. Some researchers suggest that the emplacement of lamprophyres triggers gold mineralization, whereas others hypothesize that the formation of lamprophyres increases the fertility of mantle sources and ore‐forming fluids. K‐feldspar veins, with ages between those of lamprophyres and gold deposits, appear in lamprophyres in Zhenyuan. Therefore, K‐feldspar veins are ideal for investigating the relationship between lamprophyres and gold deposits. Phlogopite in K‐feldspar veins has lower Mg#, Ni, and Cr contents and higher TiO2, Li, Ba, Sr, Sc, Zr, Nb, and Cs contents than phlogopite in lamprophyres. The in‐situ Sr isotopic values of apatites (0.7063–0.7066) in K‐feldspar veins are within the range for apatites (0.7064–0.7078) from lamprophyres. High large‐ion lithophile element concentrations and low Nb and Ta concentrations in phlogopite from lamprophyres, in addition to high (87Sr/86Sr)i values of apatite (0.7064–0.7078), indicate that the magma parental to these phlogopite and apatite crystals is derived from an enriched mantle. K‐feldspar veins are genetically correlated with lamprophyres, whereas sulfide mineral assemblage and trace element compositions of pyrite in K‐feldspar veins suggest that K‐feldspar veins in lamprophyres are not directly related to gold mineralization of the Zhenyuan deposit. [ABSTRACT FROM AUTHOR]

The low oxidation resistance of Ti3SiC2/Al2O3 composites limits their applications as high‐temperature structural materials. To improve the oxidation resistance, Nb and Ta are introduced into the substrate herein. The Nb/Ta‐doped Ti3SiC2/Al2O3 composite shows superior oxidation resistance than clean Ti3SiC2/Al2O3 following the oxidation process at 800–1000 °C for 100 h. The oxidation mechanism is determined via first‐principles calculations. The oxidation process of the composite is controlled by the inward diffusion of O and outward diffusion of Ti. When Nb/Ta elements are doped, their larger atomic radii and stronger binding produce a higher diffusion barrier for O and Ti atoms, which prevents element migration and reduces the thickness of the oxidation layers. [ABSTRACT FROM AUTHOR]

In this paper, a compact diode‐pumped continuous wave (CW) and passively Q‐switched mode‐locked (QML) Tm:YAG lasers operation on the 3F4–3H6 transition is realized by using tantalum aluminum carbide (Ta4AlC3) phase ceramic (MAX) material as a saturable absorber (SA). The first stable QML operation of the mid‐infrared Tm:YAG laser at 2012.38 nm is demonstrated with a Ta4AlC3‐SA. A stable QML Tm:YAG laser was achieved when the absorption pumping power reached 14 W. Under QML mode, Tm:YAG laser generated a maximum average output power of 560 mW at 2012.38 nm with an optical‐to‐optical conversion efficiency of 4%, corresponding to a shortest pulse duration of 541 ps and a high repetition rate of 168 MHz. The experiment shows that Ta4AlC3‐SA is an attractive candidate for diode‐pumped CW and QML mid‐infrared all‐solid‐state lasers emitting around 2.0 μm. [ABSTRACT FROM AUTHOR]

Silicide ceramics are attracted significant attention due to their exceptional physical properties. However, their inherent brittleness at room temperature limits their practical applications. Here, we aim to improve the mechanical properties of tantalum disilicide (TaSi2) ceramics by modifying the preparation methods and sintering conditions. We fabricate the dense TaSi2 ceramics using high‐pressure and high‐temperature (HPHT) sintering technology at 5.5 GPa and 800–1300°C. We characterize the microstructures, mechanical, and electronic properties of bulk TaSi2 ceramics at HPHT conditions. Our results indicate an enhancement in the fracture toughness of 11.97 MPa m1/2 for TaSi2 ceramics. More importantly, the electrical conductivity (47.13 × 105 S/m) of TaSi2 ceramic is increased and verified by theoretical calculations. These findings provide crucial insights for future applications of TaSi2 and offer valuable avenues for the design and synthesis of advanced ceramic materials. [ABSTRACT FROM AUTHOR]

Niobium and tantalum are generally found together in nature in ores such as columbite, tantalite, and pyrochlore. These ores can occasionally associate with cassiterite, the tin ore. The pyrometallurgical processes of cassiterite produces a slag that can contain Nb and Ta from the associated ores. Cassiterite processing for tin extraction has generated a considerable quantity of residue. This work aims to study the extraction of Nb from tin slag while leaving the Ta solid. The process of separation consists in one step by leaching using a combined solution of HCl‐NH4F. The slag was characterized by X‐ray fluorescence (EDXRF), atomic absorption spectroscopy (AAS), inductively coupled plasma optical emission spectrometry (ICP‐OES), X‐ray diffraction (XRD), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), and granulometric analysis. The effect of parameters of the leaching processes was investigated, such as the time of the process, HCl concentration, liquid‐to‐solid ratio, temperature, and salt‐to‐slag ratio. It was possible to recover 100% of Nb and 5% of Ta in liquor of leaching within 4 h, at 85°C, using an L:S ratio of 20:1, NH4F:slag ratio of 0.12 g, and HCl concentration equal to 9.79 mol/L. [ABSTRACT FROM AUTHOR]

The development of urgently‐needed ultraviolet (UV)/deep‐UV nonlinear optical (NLO) materials has been hindered by contradictory requirements of the microstructure, in particular the need for a strong second‐harmonic generation (SHG) response as well as a short phase‐matching (PM) wavelength. We herein employ a "de‐covalency" band gap engineering strategy to adjust the optical linearity and nonlinearity. This has been achieved by assembling two types of transition‐metal (TM) polyhedra ([TaO2F4] and [TaF7]), affording the first tantalum‐based deep‐UV‐transparent NLO materials, A5Ta3OF18 (A = K (KTOF), Rb (RTOF)). Experimental and theoretical studies reveal that the highly ionic bonds and strong electropositivity of tantalum in the two oxyfluorides induce record short PM wavelengths (238 (KTOF) and 240 (RTOF) nm) for d0‐TM‐centered oxides, in addition to strong SHG responses (2.8 × KH2PO4 (KTOF) and 2.6 × KH2PO4 (RTOF)), and sufficient birefringences (0.092 (KTOF) and 0.085 (RTOF) at 546 nm). These results not only broaden the available strategies for achieving deep‐UV NLO materials by exploiting the currently neglected d0‐TMs, but also push the shortest PM wavelength into the short‐wavelength UV region. [ABSTRACT FROM AUTHOR]

This study provides principles for designing new corrosion resistant high entropy alloys. The theoretical framework is a percolation model developed by Newman and Sieradzki that predicts the ability of an alloy to passivate, i.e., to form a protective surface oxide, based on its composition. Here, their model is applied to more complex materials than previously, namely amorphous CrFeNiTa and CrFeNiW alloys. Furthermore, the model describes a more complex passivation process: reforming the oxide layer above the transpassive potential of Cr. The model is used to predict the lowest concentration of Ta or W required to extend the passive region, yielding 11–14 at% Ta and 14–17 at% W. For CrFeNiTa, experiments reveal a threshold value of 13–15 at% Ta, which agrees with the prediction. For CrFeNiW, the experimentally determined threshold value is 37–45 at% W, far above the predicted value. Further investigations explore why the percolation model fails to describe the CrFeNiW system; key factors are the higher nobility and the pH sensitivity of W. These results demonstrate some limitations of the percolation model and offer complementary passivation criteria, while providing a design route for combining the properties of the 3d transition metal and refractory metal groups. [ABSTRACT FROM AUTHOR]

The novel electrophilic organo‐tantalum catalyst AlS/TaNpx (1) (Np=neopentyl) is prepared by chemisorption of the alkylidene Np3Ta=CHtBu onto highly Brønsted acidic sulfated alumina (AlS). The proposed catalyst structure is supported by EXAFS, XANES, ICP, DRIFTS, elemental analysis, and SSNMR measurements and is in good agreement with DFT analysis. Catalyst 1 is highly effective for the hydrogenolysis of diverse linear and branched hydrocarbons, ranging from C2 to polyolefins. To the best of our knowledge, 1 exhibits one of the highest polyolefin hydrogenolysis activities (9,800 (CH2 units) ⋅ mol(Ta)−1 ⋅ h−1 at 200 °C/17 atm H2) reported to date in the peer‐reviewed literature. Unlike the AlS/ZrNp2 analog, the Ta catalyst is more thermally stable and offers multiple potential C−C bond activation pathways. For hydrogenolysis, AlS/TaNpx is effective for a wide variety of pre‐ and post‐consumer polyolefin plastics and is not significantly deactivated by standard polyolefin additives at typical industrial concentrations. [ABSTRACT FROM AUTHOR]

River sediments are valuable archives of the environmental conditions within their catchments. The Yangtze and Yellow Rivers are the most active fluvial systems for sediment transport in East Asia, and they are regarded as potential sediment sources for the radial sand ridges (RSRs) in the southwestern Yellow Sea. We used the geochemical compositions of size‐fractioned sediment samples from the Yangtze and Yellow Rivers to characterize chemical weathering, the fractionation behavior of provenance tracers, and the sources of RSRs. For the Yangtze and Yellow River sediments, the (Rb + Sr)/Ti ratio is a reliable chemical weathering proxy that is grain‐size independent. The chemical indices of Chemical Index of Alteration, Rb/Sr, (Rb + Sr)/Ti, and acid‐leached elements from common grain‐size fractions together reveal that the Yangtze River basin undergoes stronger chemical weathering than the Yellow River basin, indicating that the chemical weathering is dominated by latitudinally‐dependent climatic variations. The dissolution and precipitation of amorphous Fe‐Mn oxides can result in the significant fractionation of La/Y, La/Sc, Nb/Co, La/Co, (La/Sm)N, (La/Yb)N, Ti/Sc, Zr/Y, Zr/Co, and Cr/Ta, whereas Zr/Ti and Zr/Nb are largely unaffected. Based on the robust provenance tracers of Zr/La, La/Hf, (La/Yb)N, Zr/Nb, Ti/Zr, and Hf/Ta, we conclude that the RSRs in the southwestern Yellow Sea are mainly derived from Yangtze River sediments, and that part of the clay fraction is from the Yellow River. In future research, we suggest that established geochemical indicators of chemical weathering and sediment provenance can be applied to the deposits of the Yangtze and Yellow River Deltas, the Yellow Sea, and the East China Sea. Plain Language Summary: The elemental composition of river sediments provides information about chemical weathering and material sources. In this study, we measured the trace and rare earth element contents of fine‐ and coarse‐grained sediment components from the Yangtze and Yellow Rivers. We established a new proxy of chemical weathering, the (Rb + Sr)/Ti ratio, which is independent of sediment grain size. Multiple chemical‐weathering proxies suggest that the degree of chemical weathering of the Yangtze River sediments is greater than that of the Yellow River sediments, based on a comparison of the same grain‐size fraction. Additionally, Zr/La, La/Hf, (La/Yb)N, Zr/Nb, Ti/Zr, and Hf/Ta were confirmed to be robust tracers of sediment provenance. The evidence of these tracers suggests that the radial sand ridges in the southwestern Yellow Sea are mainly derived from Yangtze River sediments. Key Points: (Rb + Sr)/Ti ratio is a robust grain‐size independent proxy of chemical weatheringAmorphous Fe‐Mn oxides result in the major fractionation of provenance tracers: La/Y, La/Sc, Nb/Co, La/Co, (La/Sm)N, (La/Yb)N, Ti/Sc, Zr/Y, Zr/Co, and Cr/TaYangtze River sediments are the main source of radial sand ridges in the southwestern Yellow Sea [ABSTRACT FROM AUTHOR]

We employ a metal‐metal salt metathesis strategy to access low‐valent tantalum‐copper heterometallic architectures (Ta−μ2‐H2−Cu and Ta−μ3‐H2−Cu3) that emulate structural elements proposed for surface alloyed nanomaterials. Whereas cluster assembly with carbonylmetalates is well precedented, the use of the corresponding polyarene transition metal anions is underexplored, despite recognition of these highly reactive fragments as storable sources of atomic Mn−. Our application of this strategy provides structurally unique early‐late bimetallic species. These complexes incorporate bridging hydride ligands during their syntheses, the origin of which is elucidated via detailed isotopic labelling studies. Modification of ancillary ligand sterics and electronics alters the mechanism of bimetallic assembly; a trinuclear complex resulting from dinuclear C−H activation is demonstrated as an intermediate en route to formation of the bimetallic. Further validating the promise of this rational, bottom‐up approach, a unique tetranuclear species was synthesized, featuring a Ta centre bearing three Ta−Cu interactions. [ABSTRACT FROM AUTHOR]

Uncooled broadband spectrum detection, spanning from visible to mid-wave-infrared regions, offers immense potential for applications in environmental monitoring, optical telecommunications, and radar systems. While leveraging proven technologies, conventional mid-wave-infrared photodetectors are encumbered by high dark currents and the necessity for cryogenic cooling. Correspondingly, innovative low-dimensional materials like black phosphorus manifest weak photoresponse and instability. Here, tantalum nickel selenide (Ta2NiSe5) infrared photodetectors with an operational wavelength range from 520 nm to 4.6 μm, utilizing a hexagonal boron nitride (h-BN) encapsulation technique are introduced. The h-BN encapsulated metal-Ta2NiSe5-metal photodetector demonstrates a responsivity of 0.86 A W-1, a noise equivalent power of 1.8 X 10-11 W Hz-1/2, and a peak detectivity of 8.75 X 108 cm Hz1/2 W-1 at 4.6 μη under ambient conditions. Multifaceted mechanisms of photocurrent generation in the novel device prototype subject are scrutinized to varying wavelengths of radiation, by characterizing the temporal-, bias-, power-, and temperature-dependent photoresponse. Moreover, the photopolarization dependence is delved and concealed-target imaging is demonstrated, which exhibits polarization angle sensitivity and high-fidelity imaging across the visible, short-wave, and mid-wave-infrared bands. The observations, which reveal versatile detection modalities, propose Ta2NiSe5 as a promising low-dimensional material for advanced applications in nano-optoelectronic device. [ABSTRACT FROM AUTHOR]

This study investigated the high‐temperature strength of spark plasma sintered tantalum diboride (TaB2) for the first time. TaB2 exhibited a unique elastic fracture behavior below 1900°C, unlike other transition metal diborides. The consolidation process involved spark plasma sintering at 2000–2200°C yielding dense TaB2 samples. The flexural strength was measured at elevated temperatures up to 2000°C, showing a quite high flexural strength of 400 ± 20 MPa at 1900°C. These findings provide valuable insights into the high‐temperature behavior of TaB2, highlighting its potential for advanced applications. [ABSTRACT FROM AUTHOR]

Tantalum oxynitride (TaOxN1−x) fibers were synthesized and evaluated for their electrocatalytic hydrogen activity using an in‐house developed centrifugal spinning setup. By tailoring the composition of the spinning solution and optimizing collector distance and rotation speed of the spinneret, bead‐free TaOxN1−x fibers with a diameter of 800 nm were obtained. The fibers were structurally characterized through phase and elemental analysis, confirming the formation of monoclinic TaOxN1−x with clear splitting of the X‐ray photoelectron spectroscopy peaks indicating Ta was in +5 oxidation state. The resulting oxynitride fibers exhibited superior electrocatalytic performance with low overpotentials (250 mV) to generate 10 mA/cm2 compared to Ta2O5 oxide fibers. Interestingly, the enhanced activity of oxynitride fibers was observed to be suppressed in basic medium due to the high oxophilicity of tantalum ions and a negative Gibbs adsorption‐free energy, leading to poisoning of the active sites. This work demonstrates a facile pathway for the fabrication of high‐performance electrocatalysts, based on TaOxN1−x fibers, from a cost‐effective and energy‐efficient centrifugal spinning technique. [ABSTRACT FROM AUTHOR]

The Ta/Cr/Pt three‐layer system can be used as a planar x‐ray waveguide, that is to say it can guide an x‐ray beam inside its chromium layer. This property comes from the difference in density and hence in optical index between the two "heavy" or cladding tantalum and platinum layers and the "light" or guiding chromium layer. The waveguide will be efficient provided the layers are a few nanometers thick and that the interfaces are as sharp as possible. To control the quality of the stack, we combine grazing incidence x‐ray fluorescence (GIXRF) and x‐ray reflectivity (XRR) measurements on a series of Ta/Cr/Pt samples, whose only difference is the thickness of the Cr layer. The three considered samples have been deposited by magnetron sputtering and their designed structures are: Ta (8 nm)/Cr (5, 10, and 15 nm)/Pt (14 nm)/Si substrate. The combination of XRR and GIXRF tightens constraints on the parameters used to simulate the stack: thickness, roughness, composition, and density of the layers and their interlayers. For each sample we used six GIXRF curves obtained from three different characteristic x‐ray lines (Ta Lα, Cr Kα, and Pt Lβ2,15) excited at three different incident photons energies (6.25, 10, and 12 keV) as well as one XRR curve obtained at 6.25 keV. The XRR‐GIXRF combined analysis demonstrates that the Ta/Cr/Pt structure is too simplistic and that it is necessary to introduce some interlayers at the top and bottom of the stacks to obtain a reliable agreement between the experimental and simulated GIXRF and XRR curves. [ABSTRACT FROM AUTHOR]

Two new ternary trielides Na7KTr4 (Tr=In, Tl) have been prepared by classical solid‐state reaction from the elements in tantalum ampoules. Both are isostructural to Na7RbTl4 and therefore crystallize in the orthorhombic space group Pbam, Pearson symbol oP96 (a=b=16.3283(2)/16.2860(6), c=11.3094(17)/11.2771(4), V=3015.25(8)/2991.07(18), Z=8, R1, wR2=0.0249, 0.0386/0.0447, 0.0608). The trielide subunit is built by two crystallographically independent [Tr4]8− tetrahedra. 23Na‐MAS‐Nuclear Magnetic Resonance (NMR) as well as EPR spectroscopy was employed to characterize the compounds further. DOS calculations showed a (pseudo) band gap at EF for both compounds. Dissolution experiments in liquid ammonia were carried out for the two alkali metal indides Na7KIn4 and Na2In according to the chemistry of group 14 and 15 Zintl anions. After evaporating the solvent, the remaining material was analyzed by powder X‐ray diffraction and proved the formation of NaIn and NaNH2. [ABSTRACT FROM AUTHOR]

High‐quality few‐layer M4C3Tx (M = V, Nb, Ta) MXenes are very important for applications and are necessary for clarifying their physicochemical properties. However, the difficulty in etching for themselves and the existence of MC/MC1−δ and M‐Al alloy impurities in their M4AlC3 precursors seriously hinder the achievement of defect‐free few‐layer M4C3Tx (M = V, Nb, Ta) MXenes nanosheets. Herein, three different defect‐free few‐layer M4C3Tx (M = V, Nb, Ta) nanosheets are obtained by using a universal synthesis strategy of calcination, selective etching, intercalation, and exfoliation. Comprehensive characterizations confirm their defect‐free few‐layer structure feature, large interlayer spacing (1.702–1.955 nm), types of functional groups (–OH, –F, –O), and abundant valance states (M5+, M4+, M3+, M2+, M0). M4C3Tx (M = V, Nb, Ta) free‐standing films obtained by vacuum filtration of few‐layer M4C3Tx inks show good hydrophilia, high thermostability, and conductivity. A roadmap on synthesis of defect‐free few‐layer M4C3Tx (M = V, Nb, Ta) nanosheets are proposed and three key points are summarized. This work provides detailed guidelines for the synthesis of other defect‐free few‐layer MXenes nanosheets, but also will stimulate extensive functional explorations for M4C3Tx (M = V, Nb, Ta) MXenes nanosheets in the future. [ABSTRACT FROM AUTHOR]

The Woduhe area of Heilongjiang Province is located in the eastern side of the Greater Xing'an Range. This area has experienced the evolution of the Palaeo‐Asian Ocean, the Palaeo‐Pacific, and the Mongolia–Okhotsk Ocean, and it can be used to discuss the transformation process of these palaeo‐oceanic plates to continental plates. However, controversies exist over its time period and the process of transformation. The 1:250000 Woduhe Geological Map shows that Early Cretaceous granitic batholith developed near the Dajinshan area. However, the LA‐ICP‐MS zircon U–Pb dating presented in this paper shows that the trondhjemites from the southern part of the Dajinshan area were formed at 156.9 ± 2.2 Ma, syenogranites were formed at 131.7 ± 1.6 Ma, and diorite porphyrite dikes were formed at 126.0 ± 3.1 Ma. Therefore, Early Cretaceous batholiths should be reclassified as different, separate units. The Late Jurassic intrusive rocks belong to TTGG assemblages (tonalite–trondhjemite–granodiorite‐granite). Trace element spider diagrams show that the rocks are enriched in K, Pb, Zr, and Hf; depleted in Nb, Ta, and Eu; with higher Sr; and lower Y content. The rare earth element pattern is right‐sloping (La/Yb > 12). The Early Cretaceous intrusive rocks belong to G assemblages (granodiorite). Combined with the tectonic settings, we determined that the Late Jurassic and the Early Cretaceous granites were formed in a magmatic arc setting related to subduction. Late Jurassic intrusive magma mainly originated from the partial melting of the thickened lower crust under the Xing'an arc, and was likely contaminated by mantle material. Early Cretaceous intrusive magma originated from the partial melting of the Xing'an sub‐arc crust. Based on the distribution of the Late Jurassic TTG (N and NE) and G (S and SW) assemblages, intrusive records of the southward and southwestward subduction of the Mongolia–Okhotsk Ocean can be observed. In addition, the grade of maturity of the Xing'an arc is increasing during Late Jurassic to Early Cretaceous. [ABSTRACT FROM AUTHOR]

Downward solar radiation (DSR) and air temperature (Ta) have significant influences on the thermal state of frozen ground. These parameters are also important forcing terms for physically based land surface models (LSMs). However, the quantitative influences of inaccuracies in DSR and Ta products on simulated frozen ground temperatures remain unclear. In this study, three DSR products (CMFD‐SR, Tang‐SR, and GLDAS‐SR) and two Ta products (CMFD‐Ta and GLDAS‐Ta) were used to force an LSM model in an alpine watershed in Northwest China, to investigate the sensitivity of simulated ground temperatures to different DSR and Ta products. Compared to a control model (CTRL) forced by in situ observed DSR, ground temperatures simulated by the experimental model forced by GLDAS‐SR are obviously decreased because GLDAS‐SR is much lower than in situ observations. Instead, simulation results in models forced by CMFD‐SR and Tang‐SR are much closer to those of CTRL. Ta products led to significant errors in simulated ground temperatures. In conclusion, both CMFD‐SR and Tang‐SR could be used as good alternatives to in situ observed DSR for forcing a model, with acceptable errors in simulation results. However, more care need to be paid for models forced by Ta products instead of Ta observations, and conclusions should be carefully drawn. [ABSTRACT FROM AUTHOR]

Azametallacyclopropane‐containing base stabilized borane complexes of group 5 transition metals have been synthesized and their structural aspects have been described. Treatment of Cp* based Ta and Nb chlorides, Cp*TaCl4 and Cp*NbCl4 with [LiBH4 ⋅ THF] followed by addition of ligands, such as 2‐mercaptobenzothiazole, MBT, (C7H5NS2) and 2‐mercaptobenzoxazole, MBO (C7H5NSO) led to the formation of complexes [Cp*M‐[BHS(CH2ENC6H4)(C7H4NSE)] (1: M=Ta, E=S; 2; M=Nb, E=S; 3: M=Ta, E=O; 4; M=Nb, E=O, Cp*=pentamethyl‐η5‐cyclopentadienyl). By means of UV‐vis absorption spectra, the electronic properties of these complexes associated with central metal atoms and heteroatoms (S or O) have been evaluated. In contrast, treatment of Cp*TaCl4 with 2‐mercaptopyridine, MP, (C5H5NS) under the same reaction conditions yielded the agostic σ‐borane Ta complex, [Cp*Ta(H3BNC5H4) (C5H4NS)(η2‐S2)], 5. Unlike 1–4, where the metals interact with boron through bridging sulphur, 5 shows a notable σ‐B−H bond interaction with Ta. All spectroscopic data of 1–5 along with the X‐ray diffraction studies suggest complexes 2, 4, and 5 are base (amine) stabilized borane species. Computational studies based on Density Functional Theory (DFT) also supported this conclusion. [ABSTRACT FROM AUTHOR]

Azametallacyclopropane‐containing base stabilized borane complexes of group 5 transition metals have been synthesized and their structural aspects have been described. Treatment of Cp* based Ta and Nb chlorides, Cp*TaCl4 and Cp*NbCl4 with [LiBH4 ⋅ THF] followed by addition of ligands, such as 2‐mercaptobenzothiazole, MBT, (C7H5NS2) and 2‐mercaptobenzoxazole, MBO (C7H5NSO) led to the formation of complexes [Cp*M‐[BHS(CH2ENC6H4)(C7H4NSE)] (1: M=Ta, E=S; 2; M=Nb, E=S; 3: M=Ta, E=O; 4; M=Nb, E=O, Cp*=pentamethyl‐η5‐cyclopentadienyl). By means of UV‐vis absorption spectra, the electronic properties of these complexes associated with central metal atoms and heteroatoms (S or O) have been evaluated. In contrast, treatment of Cp*TaCl4 with 2‐mercaptopyridine, MP, (C5H5NS) under the same reaction conditions yielded the agostic σ‐borane Ta complex, [Cp*Ta(H3BNC5H4) (C5H4NS)(η2‐S2)], 5. Unlike 1–4, where the metals interact with boron through bridging sulphur, 5 shows a notable σ‐B−H bond interaction with Ta. All spectroscopic data of 1–5 along with the X‐ray diffraction studies suggest complexes 2, 4, and 5 are base (amine) stabilized borane species. Computational studies based on Density Functional Theory (DFT) also supported this conclusion. [ABSTRACT FROM AUTHOR]

Designing photoanode semiconducting materials with visible‐light absorption and minimal charge‐carrier recombination for achieving efficient solar‐to‐hydrogen (STH) conversion is challenging. Here, hybrid Ta3N5 nanorods and thin films are developed on transparent GaN/Al2O3 substrates. A Ta3N5 photoanode with a loaded cocatalyst achieves the best current density, i.e. 10.8 mA cm−2, at 1.23 V versus the reversible hydrogen electrode under simulated AM 1.5G solar illumination. In a tandem configuration with dual‐CuInSe2 photovoltaic cells, this semi‐transparent photoanode achieves a reproducible STH energy conversion efficiency of ≈12% (the highest among photocatalytic materials), and remains at more than 10% for 6.7 h of tandem device operation. Detailed transient absorption spectroscopy and theoretical analysis indicates that this high performance originates from efficient light absorption and hole utilization inside the Ta3N5 material. The results show the feasibility of suppressing dominant optical and charge‐carrier‐ recombination losses by using nanostructured visible‐light‐absorbing materials for practical STH conversion. [ABSTRACT FROM AUTHOR]

Tantalum nitride (Ta3N5) has emerged as a promising photoanode material for photoelectrochemical (PEC) water splitting. However, the inefficient electron‐hole separation remains a bottleneck that impedes its solar‐to‐hydrogen conversion efficiency. Herein, we demonstrate that a core–shell nanoarray photoanode of NbNx‐nanorod@Ta3N5 ultrathin layer enhances light harvesting and forms a spatial charge‐transfer channel, which leads to the efficient generation and extraction of charge carriers. Consequently, an impressive photocurrent density of 7 mA cm−2 at 1.23 VRHE is obtained with an ultrathin Ta3N5 shell thickness of less than 30 nm, accompanied by excellent stability and a low onset potential (0.46 VRHE). Mechanistic studies reveal the enhanced performance is attributed to the high‐conductivity NbNx core, high‐crystalline Ta3N5 mono‐grain shell, and the intimate Ta−N−Nb interface bonds, which accelerate the charge‐separation capability of the core–shell photoanode. This study demonstrates the key roles of nanostructure design in improving the efficiency of PEC devices. [ABSTRACT FROM AUTHOR]

FeCrAl alloy is one of potential candidates for accident‐tolerant‐fuel (ATF)‐cladding materials due to its excellent oxidation and corrosion resistance at accident temperature, combining good mechanical properties at service temperature. Alloying strategy is an important way for improving comprehensive properties of FeCrAl alloy through the precipitation of fine Laves phase. Zr alloying can stabilize the Laves phase due to its lower diffusion coefficient and solubility in body‐centered‐cubic ferrite matrix. Herein, it is found that Zr addition changes the dynamic precipitation features of Laves phase in FeCrAl alloy during high‐temperature deformation, from only one type of Fe2M (M = Nb, Mo, Ta) Laves phase to Fe2Zr combining Fe2M‐type Laves phase. The Fe2Zr‐type Laves phase precipitates dynamically first, and the interface precipitates between which with ferrite matrix creates more nucleation sites for subsequent precipitation of Fe2M Laves phase. The results can be possibly applied for alloy design and microstructure tailoring in series of FeCrAl alloys used for ATF cladding in the near future. [ABSTRACT FROM AUTHOR]

Due to its excellent biocompatibility and corrosion resistance, tantalum demonstrates versatility as an implant material. However, limited studies investigated the role of tantalum coated titanium‐based dental implants. This study aimed to investigate the potential application of micro‐nano porous structured tantalum coating on the surface of titanium dental implant. In the present study, micro‐nano porous structured tantalum coating was prepared by vacuum plasma spraying (VPS) under selected optimum parameters, various characteristics of tantalum coating (Ta/Ti), including the morphology, potential, constituent, and hydrophilia, were investigated in comparison with its respective control groups, sandblasted titanium (Ti) and titanium coating (Ti/Ti). The adhesion, proliferation, and osteogenic differentiation ability of rat bone marrow mesenchymal cells (BMSCs) on different materials were assessed in vitro. Then the osseointegration capacity of Ti, Ti/Ti, Ta/Ti, and Straumann implants in canine mandible was evaluated with micro‐CT, histological sections, and energy dispersive X‐ray spectroscopy. These results demonstrated that micro‐nanostructured, uneven, and granular tantalum coating was successfully prepared on titanium substrate by VPS with pore size ranging from 50 nm to 5 μm and thickness ranging from 80 to 100 μm. Tantalum coating revealed the highest surface potential, best hydrophilia, and most protein adsorption among Ta/Ti, Ti/Ti, and Ti. Furthermore, Ta/Ti surfaces significantly promoted the adhesion, proliferation, and osteogenic differentiation of BMSCs. In vivo, Ta/Ti implants displayed positive osseointegration capability associated with increased bone mineral density and formation of new bone around implants without tantalum particles released. Together, these findings indicate that tantalum‐coated titanium dental implants may serve as a new type of dental implant. [ABSTRACT FROM AUTHOR]