A TiZrHfMoW-O high-entropy alloy (HEA) metal-metal oxide coating was fabricated via double-cathode glow discharge sputtering under an argon-to-oxygen (Ar:O-2) flow ratio of 30:1. Detailed microstructural analysis revealed a coating similar to 23.6 mu m in thickness, possessing a complex three-phase architecture consisting of a body-centered cubic (bcc) HEA metallic phase, a spinel-type high-entropy oxide (HEO) phase, and a face-centered cubic (fcc) oxide phase. The coating exhibited a heterogeneous microstructure across its cross-section, transitioning from equiaxed grains, similar to 20 nm in diameter, in the inner region to ultra-fine grains, similar to 2 nm in diameter, in the outer region. High-resolution TEM confirmed the co-existence of all three phases within individual microstructural domains, forming ultra-fine grain clusters together with intricate phase boundaries that enhance mechanical properties through interfacial strengthening. Additionally, the coating exhibited a compressive residual stress, further contributing to its hardness. The maximum hardness reached similar to 22.6 +/- 0.2 GPa-approximately 2.4 times higher than its fully metallic, oxygen-free TiZrHfMoW counterpart (similar to 9.6 +/- 0.8 GPa). These findings demonstrate that partial oxidation during sputtering can significantly strengthen HEA coatings through multiple synergistic mechanisms.

MXene-based proton pseudocapacitors are promising candidates for microscale electronic devices due to their superior portability and high-power density, yet their advancement is constrained by the scarcity of efficient electrode materials. Herein, a nitrogen-directed Ti3C2Tx MXene with substitution of terminal functional groups by nitrogen is proposed as a high-efficiency electrode material for proton pseudocapacitors. This strategy introduces multiple surface-active sites and a new pathway for fast proton storage for achieving high specific capacitance. Impressively, a nitrogen-directed proton storage mechanism is unraveled in the terminal N groups can preferentially interact with protons and lower the diffusion energy barrier toward adjacent active-sites, substantially facilitating the storage of protons. As a result, the N300-Ti3C2Tx delivers excellent capacitance retention of 84.48% after 30,000 cycles at 2 A g-1. Furthermore, in-plane proton pseudocapacitors are fabricated via direct ink writing, which shows great compatibility with various connection configurations, validating the superior potential in application feasibility of the N-directed Ti3C2Tx on proton storage.

Uranium ore concentrate (UOC) is a group of intermediate products widely used in the nuclear fuel cycle. Following the recent characterisation and classification of UOC industrial product powders for nuclear forensic analysis, this paper presents an experimental study of the hygroscopic properties of these UOC stockpile samples for long-term storage and the inhalation risk assessment of uranium particles. Two independent techniques, the density balance and Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), were utilised to measure increases in sample weight and the infrared absorption peak of ten UOC samples, respectively, due to hygroscopic growth. Taking (NH4)4((UO2)2(SO4)O2)2(H2O) powder as an example, the hygroscopicity mechanism was investigated experimentally by monitoring hydration and dehydration processes using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and Thermogravimetric-Differential Thermal Analysis (TG-DTA), respectively. The hygroscopic growth factor of (NH4)4((UO2)2(SO4)O2)2(H2O) sample was determined using the above two techniques under precisely controlled temperature and humidity conditions. Screening results show significant differences in the hygroscopicity of sodium- and ammonium-containing UOC powders, despite their similar elemental composition, infrared functional groups, and crystal structures. The porous surface and hygroscopic component are beneficial for hygroscopic growth. Observation of the hydration and dehydration process confirms that the physical adsorption of water is the dominant mechanism. The hygroscopic growth factors of sample mass and infrared absorption peak increase with rising relative humidity above 80% RH. The hygroscopic growth curve of (NH4)4((UO2)2(SO4)O2)2(H2O) powder could be described using a simplified κ-Köhler equation. A dense surface, low RH (<80%) and an inert buffer gas are recommended for material processing and stable storage. For (NH4)4((UO2)2(SO4)O2)2(H2O) particles possibly inhaled in the respiratory tract, the effect of hygroscopic growth on the deposition profile is also discussed.

To enhance the mechanical and tribological properties of titanium alloys and address the inherent limitations of single coatings in achieving satisfactory performance improvement, this study draws inspiration from the protective structure of armor and proposes an innovative two-stage plasma electrolytic oxidation (PEO) strategy, which differs from conventional single-step treatments. By alternating treatments in silicate and phosphate-based electrolytes, a hard-wear-resistant coating architecture was constructed on the titanium alloy surface, achieving optimal tribological and mechanical performance. Compared with the substrate, the coating exhibited a twofold increase in microhardness and more than an order of magnitude reduction in wear rate. The main innovation of this work lies in the sequential use of different electrolyte systems rather than their simple mixing or individual application, enabling the construction of a composite ceramic coating with a TiO2-rich armoring layer, increased thickness, and improved mechanical stability. Wear tests conducted under loads ranging from 1 N to 7 N confirmed the reliability and stability of the composite coating. This study demonstrates the feasibility of tailoring tribological interface structures on titanium alloys through the two-stage PEO technique, offering a viable pathway for enhancing their mechanical performance and opening new avenues for their application in tribology and engineering fields.

Introducing interstitial atoms into a metallic lattice to manipulate its electronic structure and coordination environment is an effective strategy for enhancing the performance of the electrocatalytic oxygen evolution reaction (OER). In this study a one-step sputtering deposition method was employed to introduce interstitial nitrogen into FeCoNi microarray coatings enabling the synthesis of transition metal interstitial nitrides (FeCoNi TMINs). Acting as potential electron reservoirs, nitrogen atoms induce charge redistribution and promote the formation of additional metal-nitrogen ligands. This process leads to lattice distortion which exposes more active sites and disrupts the symmetry of the FeCoNi crystal structure, thereby modulating orbital electron occupancy. In alkaline electrolytes, the FeCoNi TMINs containing 3 at% interstitial N exhibit optimal intrinsic catalytic performance, achieving remarkably low overpotentials of 244 and 388 mV at current densities of 10 and 400 mA cm(-2), respectively, along with robust stability at 400 mA cm(-2) for 300 h. Complementary theoretical calculations reveal that a uniform distribution of interstitial nitrogen at this optimal concentration initiates rapid surface reconstruction of the FeCoNi TMINs by coordinating two key processes: ion leaching and pre-oxidation. This transformation facilitates the formation of highly active FeCoNiOOH species at a lower potential. This work elucidates the fundamental structure-activity relationship between interstitial nitrogen and OER performance, providing new insights for the rational design of next-generation OER catalytic systems with simultaneously optimized activity and stability.

Electrocatalytic water splitting represents a promising route for green hydrogen production; however, the development of efficient non-noble electrocatalysts remains a major challenge to enhancing energy conversion efficiency. Herein, a binder-free in situ growth strategy is proposed to fabricate a V-doped MoS2/Co3S4/NiS@NF electrocatalyst for the hydrogen evolution reaction (HER), utilizing a bivanadyl-capped crystalline polyoxometalate-based coordination polymer (POMCP) [(pytpy)2[PMo12O40(VO)2]·6H2O] as a molybdenum/vanadium dual precursor. Cobalt acetate and thiourea serves as the cobalt and sulfur sources, respectively, whereas nickel foam functions as both a 3D conductive substrate and a nickel source. The homogeneous multimetal dispersion derived from the POMCP precursor, together with the binder-free in situ construction, promotes intimate interfacial contact, suppresses particle agglomeration, optimizes interfacial electronic distribution, and enhances structural stability. MoS2/Co3S4/NiS@NF exhibits high HER performance with a low overpotential of 61mV to achieve 10mAcm-2, with a Tafel slope of 135mV dec-1 and a Faradaic efficiency of 94.2%. Notably, V doping induces S vacancies, modulates the d-band center of active sites, and accelerates charge transfer. Meanwhile, strong electronic coupling among MoS2, Co3S4, and NiS phases increases active-site exposure and optimizes reaction thermodynamics. Theoretical calculations further reveal that Sv-V-Co3S4 serves as the dominant catalytic phase and that directional interfacial electron transfer modulates the thermodynamics of the alkaline HER reaction pathway and intermediate adsorption. This work provides a feasible and controllable strategy for designing trimetallic sulfide electrocatalysts via POMCP-derived multimetallic regulation.

With the growing demand for high-performance die materials under harsh service conditions, the development of composite coatings with enhanced hardness and wear resistance has attracted significant attention. In this study, homogeneous laser cladding was employed to fabricate H13 alloy coatings reinforced with varying TiC contents (0, 10, 20, and 30 in wt.%) on H13 steel, which minimizes compositional segregation and ensures strong metallurgical bonding. TiC particles acted as heterogeneous nucleation sites during solidification, refining the microstructure and enhancing phase stability. The coatings consisted of initial TiC residues, newly formed primary and eutectic TiC, as well as austenite and martensite phases. With increasing TiC addition, TiC morphology evolved from fine particles to complex fishbone-like and polygonal structures. The coating containing 30% TiC achieved the highest hardness of 1095.9 HV0.5, approximately five times that of the as-annealed H13 steel substrate while the 20% TiC coating exhibited optimal high-temperature wear resistance. Under the sliding conditions at 600 °C, the friction coefficient decreased from 0.467 for the substrate to 0.367 for the 20% TiC coating, accompanied by a remarkable reduction in wear rate from 27.45 × 10−4 mm3 N−1 m−1 to 4.32 × 10−4 mm3 N−1 m−1. The superior performance was attributed to the multiscale TiC reinforcement mechanism: initial TiC promoted grain refinement and strong interfacial bonding, in situ formed primary TiC induced lattice distortion and dislocation strengthening, and eutectic TiC reinforced grain boundaries, jointly enhancing hardness, thermal stability, and wear resistance.

As the demand for clean energy continues to rise, hydrogen has attracted significant attention due to its high energy density and conversion efficiency. Efficient hydrogen separation and purification technologies are crucial for its industrial application. In this study, density functional theory (DFT) calculations, combined with molecular dynamics (MD) simulations, are employed to systematically investigate the hydrogen separation performance and elucidate the underlying mechanisms of Pd-Ag-based alloy membranes (Pd-Ag-Y and Pd-Ag-Ni). Our results indicate that doping with Y and Ni significantly enhances the structural stability of the alloy membranes and effectively reduces the hydrogen diffusion energy barrier. Notably, the Pd-Ag-Y membrane demonstrates the highest hydrogen permeability. Further analysis reveals that the incorporation of Y and Ni substantially improves the hydrogen selectivity of the alloy membranes over other gases, including N2, CO, CO2, CH4, and H2S. In most cases, their selectivity exceeds industrial thresholds, further enhancing the efficiency of hydrogen separation. The MD simulation results are in excellent agreement with the DFT calculations, validating the superior performance of the alloy membranes in hydrogen separation. This study demonstrates that judicious dopant selection, especially the incorporation of yttrium (Y), can simultaneously enhance hydrogen permeability and suppress impurity transport in Pd-Ag-based membranes, offering a promising pathway for designing high-performance ternary alloy membranes for gas separation.

A dense nanocrystalline titanium nitride (TiN) nitrided layer was deposited on TC6 titanium alloy by plasma nitriding to address its low surface hardness and limited corrosion resistance. XRD and SEM analyses confirmed a uniform, compact TiN nitrided layer with high crystallinity and preferred (200) orientation. Nanoindentation revealed markedly higher hardness, modulus, and elastic recovery than the substrate, indicating enhanced wear resistance. Electrochemical tests in 3.5 wt.% NaCl exhibited a higher corrosion potential, reduced current density, and increased charge-transfer resistance, confirming superior corrosion protection. Cavitation erosion tests with electrochemical noise and wavelet analysis further demonstrated stable passivation and resistance to cavitation damage.

Thermal ionization mass spectrometry (TIMS) is a widely used mass spectrometric technique for trace/ultra-trace isotopic analysis. For accurate isotope ratio determination, the detector dead time and ion counter efficiency have to be appropriately corrected for. Two methods of pulse counting detector dead time calculation were evaluated on a TIMS instrument. Both methods were based on the measurement of Sr isotope ratios in NIST standards and had similar performance in assessing the dead time for pulse-count detectors. In addition, one of the newly proposed methods in this manuscript can be used to simultaneously determine the dead time and ion counter efficiency of the pulse counting detector via the ratio measurement approach. The advantages of using the method presented here are firstly that both the detector dead time and the ion counter efficiency can be obtained simultaneously and secondly that the sampling time can be spent entirely on the isotopes of interest.

Inspired by the hierarchical architectures found in natural materials, a TiZrHfMoW/(Mo,W)N gradient multilayer coating was fabricated using a simple one-step sputtering deposition technique, leveraging segregation-induced self-assembly rather than conventional sequential deposition. During the deposition process, the spontaneous segregation of W and Mo led to the formation of a layered (Mo,W)N phase within the TiZrHfMoW matrix. These sublayers exhibit epitaxial relationships with the surrounding high-entropy alloy phase, forming well-defined coherent interfaces. Compared to a monolithic (Mo,W)N coating, the gradient multilayer system maintains comparable surface hardness (similar to 18.8 GPa) while significantly enhancing damage tolerance under mechanical loading. The synergistic toughening mechanisms include solid solution strengthening, interface coherency strain, grain boundary hardening, and a spatially varying modulus that aids crack arrest and stress distribution. This work demonstrates a scalable, self-organizing design strategy for architectured coatings with offering superior mechanical performance under demanding service conditions.

The efficient discovery of novel hydrogenated perovskite materials (ABH) with superior hydrogen storage capacity presents a significant challenge, primarily due to the limitations of traditional trial-and-error methods and the vast unexplored compositional space. First-principles approaches, while accurate in calculating molecularscale electronic properties and guiding experimental material design, are time-intensive for exploring all possible perovskite combinations. To meet this challenge, we developed a streamlined and efficient machinelearning framework for high-throughput screening, enabling the rational design of ABH materials with enhanced hydrogen storage capacity. Our methodology begins with the construction of a comprehensive database of material properties, followed by feature engineering to identify key attributes that influence hydrogen storage capacity. By introducing novel descriptors, such as the d-band center, which require low-cost computations, we significantly reduce the required volume of training data. The RF and GBDT algorithms exhibited superior performance, achieving R2 values of 0.86 and 0.78, respectively, underscoring the reliability of our predictive model. Furthermore, we employed Shapley additive explanations (SHAP) to enhance model interpretability, revealing that the d-band center is a critical determinant of hydrogen storage performance. This study addresses the lack of efficient design strategies for ABH materials by integrating machine learning with firstprinciples calculations into a unified screening framework. It not only provides a rapid screening approach for high-performance perovskites and other nanomaterials, but also offers a cost-effective strategy to enhance the accuracy of machine learning models in material science. Our framework establishes a strong foundation for accelerating the design and discovery of advanced hydrogen storage materials.

Transition metal‐based catalysts with high efficiency and stability for overall water splitting (OWS) offer significant potential for reducing green hydrogen production costs. Utilizing sputtering deposition technology, we propose a deposition‐diffusion strategy to fabricate heterojunction coatings composed of ultrafine FeCoNi‐C‐N transition metal interstitial solid solution (TMISS) nanocrystals and amorphous nitrided carbon (NC) on the pre‐deposited NC micro column arrays. The diffusion of C and N atoms results in the formation of uniformly distributed TMISS nanocrystals, with an average diameter of ~1.9 nm, thus maximizing atomic utilization. The unique crystalline‐amorphous heterojunction interface enhances electrocatalytic stability. Furthermore, the electronic regulation of metal sites by interstitial C and N atoms not only optimizes the adsorption‐dissociation process in hydrogen evolution reaction (HER), but also accelerates the surface reconstruction of hydroxyl oxides to enhance the oxygen evolution reaction (OER) activity. As a result, the as‐prepared coating achieved overpotentials of only 62 and 237 mV for the HER and OER at 10 mA cm−2 in alkaline electrolytes, and exhibited excellent OWS performance and long‐term stability at high current densities. This work presents a new perspective for synthesizing TMISS nanocrystals and promotes their application in bifunctional electrocatalysts.

MoS2 has been widely explored as an electrode material for aluminum-ion batteries (AIBs); however, its practical application is hindered by poor electrical conductivity and limited cycling stability. Constructing heterostructures has emerged as an effective strategy to overcome these challenges. Nevertheless, the distinct roles and underlying mechanisms of different types of heterostructures, particularly lateral and vertical configurations, in AIBs remain to be fully elucidated. In this study, we perform a systematic first-principles analysis of the MoS2/NiS heterostructure, revealing excellent stability and metallic characteristics. Regarding electrochemical performance, the vertical heterojunction exhibits minimal lattice mismatch, a diffusion energy barrier of 1.34 eV, an open-circuit voltage (OCV) of 1.43 V, and a theoretical specific capacity of 353.17 mAh/g. These properties make it a promising cathode material with enhanced energy density and cycling stability. In contrast, the lateral heterojunction demonstrates a lower diffusion barrier (0.74-0.92 eV), an OCV of 0.33 V, and a higher specific capacity (476.87 mAh/g), enabling excellent rate performance as an efficient electron donor during discharge. This study provides valuable theoretical insights into the potential application of MoS2/NiS heterostructures in AIBs, offering significant prospects for improving AIB performance and advancing the development of efficient energy storage and conversion technologies.

Superlubricity, a cutting-edge concept that eliminates energy losses caused by friction and wear, holds significant promise for enhancing the lifespan of components and promoting carbon neutrality in microelectromechanical systems. However, achieving superlubricity of WS2 on silicon surfaces and elucidating its underlying mechanisms remain challenging. Here, we investigate the electronic properties and atomic-scale friction of WS2 micro/nanoelements on silicon-based surfaces using first-principles calculations based on density-functional theory. Our results demonstrate that the graphite/WS2 heterostructures on silicon substrates can achieve an average friction coefficient as low as 10-3, primarily attributed to the elimination of edge pinning effects. However, under humid conditions, the superlubricity between graphite/WS2 interfaces is disrupted due to the formation of H-S covalent bonds, which increase interfacial adhesion. This work provides novel insights into the lubrication mechanisms of WS2 and significantly advances our understanding of the frictional properties of two-dimensional materials, highlighting their potential applications in various technological fields.

To develop an electrically conductive, yet corrosion resistant, coating for metallic bipolar plates used in proton exchange membrane fuel cells (PEMFCs) environments, a series of novel (TiVCrNbMo)N high-entropy nitride (HEN) coatings were deposited in a mixed N2/Ar atmosphere using a double-cathode glow discharge system. The influence of varying N2/Ar flow ratios on the electrochemical corrosion behavior and interfacial contact resistance (ICR) of the coatings was systematically investigated to inform the development of high-performance protective coatings for metallic bipolar plates. All the HEN coatings exhibited a single-phase face-centered cubic (FCC) solid solution with equiaxed nanoscale grains. Corrosion resistance in a simulated acidic PEMFC environment was evaluated using a range of electrochemical analytical approaches. The results indicated that the icorr values and the current density at a potential of +0.6 VSCE for the HEN coatings prepared at N2:Ar flow ratios of 1:10 and 1:5 coating are of the order of 10- 8 Acm- 2 and 10- 7 A cm- 2, respectively, both of which are three orders of magnitude less than that for the uncoated CP-Ti. Regardless of whether measurements were taken before or after potentiostatic polarization, the ICR values of the as-deposited HEN coatings decreased with increasing N2/Ar flow ratio under a compaction force of 140 N cm- 2. In particular, for the HEN coating prepared at a N2:Ar flow ratio of 1:5, the ICR values are 16.2 and 20.4 m Omega & sdot;cm2 before and after potentiostatic testing, respectively, which approach the US DOE 2025 target for surface resistance of metallic BPs. Furthermore, firstprinciples calculations were used to assess the impact of surface passive films on the coatings'electrical conductivity.

Cavitation erosion damage is a significant issue in marine applications, where fluid flow causes severe deterioration of surface components, reducing their service life and reliability. To address this challenge, a (TiZrNbTaMo)N refractory high-entropy nitride (RHEN) nanocrystalline coating with a single-phase rock-salt crystal structure was synthesized onto a titanium alloy (TC4) substrate via a glow discharge deposition method. This RHEN coating, composed of equiaxed nanocrystals with an average size of similar to 11.3 nm, exhibited a hardness of 39.3 +/- 0.5 GPa, approaching the threshold for superhard materials (40 GPa). Cavitation erosion resistance was evaluated using a magnetostrictive-induced ultrasonic cavitation system, comparing the coated specimen with the uncoated titanium alloy substrate. Various electrochemical methods were employed to monitor the electrochemical behavior of the RHEN coating under different cavitation durations in an artificial seawater environment. After different cavitation erosion periods, the RHEN coating significantly enhanced the corrosion resistance of the TC4 alloy, shifting the free corrosion potential in a more noble direction and reducing corrosion current densities (i(corr)) by one to two orders of magnitude, respectively. After 12 h of cavitation testing in an artificial seawater solution, the cumulative weight loss of the uncoated TC4 alloy is about five times higher than that of the RHEN coating. The superior cavitation erosion-corrosion resistance of the RHEN coating demonstrates its potential as an effective protective layer for metallic components operating in fluid environments.

Developing efficient and durable Pt‐based catalysts via interface engineering remains a critical yet challenging task for water electrolysis under high‐pH conditions. Herein, we design a unique asymmetric Pt─O─Cu ligand at the PtCu 2 (111)/CuO(002) heterojunction interface to promote alkaline HER kinetics. This ligand balances the adsorption and desorption of H* on the Pt site by accelerating electron transfer at the interface while enhancing the adsorption of H 2 O on the Cu site. Moreover, the strong d‐d/sp hybridization and more delocalized d‐DOS located at the Pt─O─Cu ligand enhance the interatomic interactions, which helps alleviate the dissolution and agglomeration of Pt and Cu atoms. As anticipated, the PtCu 2 /CuO requires ultra‐low overpotentials of 10, 14 and 47 mV in, respectively, alkaline, acidic and neutral electrolytes to achieve a current density of 10 mA cm −2 . Even more surprising is that the PtCu 2 /CuO||RuO 2 dual‐electrode hydrolysis cell can stably operate at a high current density of 1 A cm −2 for more than 500 h in a simulated industrial environment, demonstrating significant potential for industrial applications. This work provides a new paradigm for the design of industrially relevant high‐performance Pt‐based alkaline hydrogen evolution catalytic materials.

Humidity sensors are crucial for various applications, including human healthcare, agriculture, storage environments, and the Internet of Things. Historically, sensing materials have struggled with long response and recovery times and small response amplitudes. In this work, we propose and investigate a method for evaluating the relative humidity sensitivity of NiPS3 using first-principles calculations. Parameters such as adsorption properties, charge transfer, density of states, and I-V relationship were considered. Our findings show that NiPS3 exhibits enhanced selective sensitivity and rapid response to H2O compared to other gases, consistent with previous experimental results. NiPS3 exhibited high current sensitivities of 36.34 % to H2O at a bias voltage of 0.6 V, with the relative selectivity of H2O compared with other gases ranging from 6.7 to 17.2. Moreover, theoretical studies on sensor variation with relative humidity indicated that significant physisorption behavior increases conductivity and sensing efficiency under high concentrations of H2O. Our analysis not only demonstrates the potential of NiPS3 for humidity sensing applications but also offers a conceptual framework for designing nanomaterial-based humidity sensors, laying a solid theoretical foundation for the further development of efficient humidity sensors.

Rational modulation of surface reconstruction in the oxygen evolution reaction (OER) utilizing defect engineering to form efficient catalytic activity centers is a topical interest in the field of catalysis. The introduction of point defects has been demonstrated to be an effective strategy to regulate the electronic configuration of electrocatalysts, but the influence of more complex planar defects (e.g., twins and stacking faults), on their intrinsic activity is still not fully understood. This study harnesses ultrasonic cavitation for rapid and controlled introduction of different types of defects in the FeCoNi/FeAl 2 O 4 hybrid coating, optimizing OER catalytic activity. Theoretical calculations and experiments demonstrate that the different defects optimize the coordination environment and facilitate the activation of surface reconstruction into true catalytic activity centers at lower potentials. Moreover, it demonstrates exceptional durability, maintaining stable oxygen production at a high current density of 300 mA cm −2 for over 120 hours. This work not only presents a novel pathway for designing advanced electrocatalysts but also deepens our understanding of defect-engineered catalytic mechanisms, showcasing the potential for rapid and efficient enhancement of electrocatalytic performance.