Multicomponent Metal Research Articles

Advancing the thermodynamic modeling of multicomponent phases in hydrogen-para-equilibrium

We present an advanced approach for the thermodynamic modeling of metal hydrides within the Calculation of Phase Diagrams (CALPHAD) framework. As the traditional CALPHAD method requires significant and time-consuming manual input, often introducing biases into the assessment process, we present a novel solution to automate this. The core of our approach is the development of an open-source, Python-based computational tool designed to calculate para-equilibrium states in hydrogen-multicomponent phases. This tool facilitates a semi-automatic pathway to enhance the CALPHAD evaluation procedure, significantly reducing manual input. We validated our approach by rapidly assessing the (Ce,La)Ni5–H system, a representative material system with significant implications for metal hydride-based hydrogen applications. Our method confirms existing data and reveals new insights into this system’s sorption properties and phase behavior. Using our Python-based tool to optimize parameter sets and calculate Pressure-Composition-Isotherms (PCI), we demonstrate the feasibility of predicting temperature-dependent plateau pressures and hydrogen capacities of multicomponent metal hydrides. This work holds significant potential for future applications in designing hydrogen storage materials, predicting their properties, and extending the methodology to other metal hydride systems.

Optimization of density and cost in the prediction of solid solution formation of multicomponent metal alloys

Multicomponent alloys or high-entropy alloys (HEAs) are the most recent breakthroughs in the metal alloying area. Their unique possibilities in mechanical properties and their vast universe of combinations turn them into a highly active research area. The properties of HEAs depend on the solid solution formation, which can be predicted by calculation. Therefore, we present a method to simulate discrete compositions of the alloy elements in the software MD 2.0, created to calculate four parameters and provide their associated statuses to predict the solid solution formation in multicomponent alloys. The HEA CoCrCuFeNi was subjected to calculation in MD 2.0, and, if all the imposed restrictions and criteria are concomitantly attended: (a) the minimum density (8.426 g/cm3) solid solution formation refers to 33.122% Co, 6.491% Cr, 9.984% Cu, 34.909% Fe, and 15.494% Ni composition; (b) the minimum specific cost (US$/kg 7.560) under solid solution formation addresses 5.059% Co, 5.174% Cr, 31.553% Cu, 33.975% Fe, and 24.239% Ni composition. Given this result, it is possible to select the optimized composition of the alloy according to the design objective.

Enhanced ammonia yield rate from nitrogen on collapsed dodecahedral-shaped Co/NC electrocatalyst

Nowadays, multi-component non-precious metal catalysts have been considered as a significant strategy for enhancing the yield of synthesizing NH3 by electrocatalytic nitrogen reduction reaction (E-NRR). In the present work, carbon composites doped with well-dispersed Co and N (Co/NC) were prepared by pyrolyzing zeolitic imidazolate framework-67 (ZIF-67) at various temperatures protected under a N2 flow. Co/NC exhibits a collapsed dodecahedral morphology with a mesoporous structure (3.5-4 nm). The chemical states of Co/N and the structural defects of C are closely related to the carbonization temperature. In a N2-saturated 0.1 M KOH electrolyte, the as-prepared catalysts exhibit an NH3 yield rate (Y(NH3)) of 60.57 μg h-1 mgcat.-1 and a Faradaic efficiency (FE) of 23.3% at -0.1 V (vs the reversible hydrogen electrode, RHE) at ambient conditions. The enhanced E-NRR activity of Co/NC may primarily originate from an associative distal pathway on the Co-N3-C sites and the carbon defects in an alkaline electrolyte. Specifically, this work presents a three-component E-NRR catalyst with excellent stability and great activity based on Co/NC.

Concurrent Amorphization and Nanocatalyst Formation in Cu-Substituted Perovskite Oxide Surface: Effects on Oxygen Reduction Reaction at Elevated Temperatures.

The activity and durability of chemical/electrochemical catalysts are significantly influenced by their surface environments, highlighting the importance of thoroughly examining the catalyst surface. Here, Cu-substituted La0.6Sr0.4Co0.2Fe0.8O3-δ is selected, a state-of-the-art material for oxygen reduction reaction (ORR), to explore the real-time evolution of surface morphology and chemistry under a reducing atmosphere at elevated temperatures. Remarkably, in a pioneering observation, it is discovered that the perovskite surface starts to amorphize at an unusually low temperature of approximately 100 °C and multicomponent metal nanocatalysts additionally form on the amorphous surface as the temperature raises to 400 °C. Moreover, this investigation into the stability of the resulting amorphous layer under oxidizing conditions reveals that the amorphous structure can withstand a high-temperature oxidizing atmosphere (≥650 °C) only when it has undergone sufficient reduction for an extended period. Therefore, the coexistence of the active nanocatalysts and defective amorphous surface leads to a nearly 100% enhancement in the electrode resistance for the ORR over 200 h without significant degradation. These observations provide a new catalytic design strategy for using redox-dynamic perovskite oxide host materials.

Fabrication of CoM (M= Ni, Cu) alloys modified carbon electrocatalysts by pyrolysis of dual-metal-site metal-organic frameworks for efficient dye-sensitized solar cells

The regulation of interface properties of multi-component transition metals in carbon-based catalyst has been an effective method to boost the electrochemical performance of counter electrode (CE) catalysts for dye-sensitized solar cells (DSSCs). Herein, CoNi-metal-organic framework (MOF) and CoCu-MOF are fabricated through introducing Ni and Cu into the stable Co-MOF, and used as sacrificial precursor in the followed pyrolysis-alloying process. And then, the target product CoM (M=Ni, Cu)/N-doped polyhedron-like carbon (NC) are successfully obtained, in which CoNi and CoCu alloy nanoparticles are uniformly dispersed on the N-doped carbon skeleton. Such MOFs-derived carbon matrix can not only supply as conductive network, but also isolate the alloy nanoparticles to avoid agglomeration, ensuring more effective active sites. Meanwhile, the built-in electric field generated by the Mott-Schottky interface effect of CoM/NCs could regulate the electronic structure inside the catalysts, resulting in faster electron transfer ability. Significantly, the reduced work function due to the introduction of Cu atoms leads to stronger self-driven electron transfer at the heterogeneous interface of CoCu/NC, which helps to improve reaction activity and electrocatalytic efficiency. Among the tested catalysts, CoCu/NC displays a more satisfying power conversion efficiency (PCE) of 7.60 % when assembled into CE of DSSC, also superior to 7.19 % of Pt.

An Investigation of the Interface between Transition Metal Oxides (MnOx, FeOx, CoOx and NiOx)/MoO3 Composite Electrocatalysts for Oxygen Evolution Reactions

This study presents the synthesis of a multicomponent metal oxide electrocatalyst that increases the activity of the oxygen evolution reaction (OER). We synthesized transition metal oxides (MnOx, FeOx, CoOx, and NiOx) with MoO3 heterostructures through a solid-state reaction approach at low cost. In comparison to the other compositions, CoOx garnered higher attention and demonstrated superior performance on account of its large surface area and varied crystal facets. The MnOx-MoO3, FeOx-MoO3, CoOx-MoO3, and NiOx-MoO3 compositions attained an overpotential of 390 mV, 350 mV, 310 mV, and 340 mV, respectively, at a current density of 10 mA cm−2 in alkaline solution. The performance of OER was enhanced in CoOx-MoO3 at 10 mA cm−2, while FeOx-MoO3 exhibited a lower current density at 100 mA cm−2 than other metal oxides. The CoOx-MoO3 material exhibited a favorable crystal interface transition due to the presence of MoO3 oxide. For the first time, we report on the MoO3-to-(MnOx, FeOx, CoOx, and NiOx) interface crystal transition and the active surface area for OER catalytic activity in water-splitting processes. This investigation intends to develop an electrocatalyst that is capable of producing hydrogen with the use of heterostructure metal oxides.

Anionic surfactant-activated remediation of Pb, Cd, As contaminated soil by electrochemical technology

Lead (Pb), cadmium (Cd) and arsenic (As) contamination in soils show a growing environmental concern. However, owing to the significant differences in chemical characteristics, remediating heavy metal(loid)s of Pb, Cd and As is challenging. Herein, anionic surfactant-activated electrochemical approach was proposed to realize efficient immobilization of As, Cd and Pb heavy metal(loid)s from contaminated soils. In this innovative method, calcium lignosulfonate (CL) as anionic surfactant was used to activate Cd and Pb from contaminated soils into solution, afterwards anodically generated Fe (II) ions by the electrochemical process react with Pb and Cd to form precipitates. Meanwhile, owing to the strong binding capacities of Fe (II) ions, As contaminations were remediated. Moreover, via various characterizations and cyclic voltammetric method, the reaction kinetics and phase transformation process during the electrochemical process were analyzed in detail. These findings show great potential in optimizing the design of electrochemical treatment, which will be applied in remediating multi-component heavy metal(loid) polluted soils.

Gold Nanocluster-Based Self-Assembly Fluorescence Microbeads for Sensor Array Discrimination of Multicomponent Metal Ions.

Benefiting from easy visualization and simultaneous detection of multiple targets, fluorescence microbeads are commonly used as fluorescence-sensing elements to detect pollutants in the environment. However, the application of fluorescence microbead-based sensor arrays is still limited because fluorescence dyes always suffer from self-quenching, photobleaching, and spectral overlap. Herein, three kinds of gold nanoclusters (Au NCs) were assembled with polystyrene microspheres (PS NPs) by electrostatic interaction to prepare fluorescence microbeads (PS-Au NCs), developing a sensor array for the simultaneous analysis of multiple metal ions. In this work, different PS-Au NCs showed an enhancing or quenching fluorescence response to various metal ions, owing to distinct binding capacities. Combined with the recognition algorithm from linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA), this sensor assay could realize single-component and multicomponent qualitative detection for 8 kinds of heavy metal ions (HMIs) including Cu2+, Co2+, Pb2+, Hg2+, and Ce3+. Particularly, the large surface area of PS NPs could provide a direct reaction microenvironment to improve the efficiency of the detection process. Meanwhile, the fluorescence property of Au NCs could also be enhanced by a partially effective aggregation-induced emission (AIE) effect to give better fluorescence signal output. Under optimal conditions, 8 kinds of heavy metals and their multicomponent mixtures could be identified at concentrations as low as 0.62 μM. Meanwhile, the analytical performance of this sensor assay in water samples was also verified, meeting the requirement of actual analysis. This study provides a great potential and practical example of single-batch, multicomponent identification for HMIs.

Tuning Morphologies of Metal-Organic Framework-Derived Ni3P/Ni Carbon Nanocomposites for Water Oxidation.

The oxygen evolution reaction (OER) frequently acts as a kinetic bottleneck in various energy storage and conversion systems. Effective electrocatalysts for the OER play a crucial role in reducing the reaction barrier and expediting the reaction. Multicomponent transition metal phosphides (TMPs) have garnered an extensive amount of attention as a result of their exceptional performance in the OER. Here, we present a direct method for preparing two intrinsic morphologies of metal-organic frameworks (MOFs), barrel-like BMM-10 and pancake-like BMM-10(Ac), achieved by establishing a protonation/deprotonation equilibrium with varying NO3-/Ac- ratios. The BMM-10(Ac)-C catalyst was synthesized via heat treatment of the BMM-10(Ac) precursor, exhibiting superior OER performance. It realized an overpotential of 286 mV at a current density of 10 mA cm-2, with a Tafel slope of 111.17 mV decade-1 and a current retention of 98.03%. This improvement arises from the synergistic interaction between Ni3P/Ni nanoparticles and the partially graphitic carbon layer, augmenting the exposure of active sites. Furthermore, alterations in the morphological features of MOF-derived Ni3P/Ni carbon nanocomposites adjusted the active electrochemical surface area, thereby modulating the overall OER performance of the corresponding TMP carbon nanocomposites. This methodology can be extended to control the morphology of other MOFs and their derivatives, providing innovative avenues for the design and synthesis of new MOF-based TMP nanomaterials.

Local-distortion-informed exceptional multicomponent transition-metal carbides uncovered by machine learning

Developing high-performance multicomponent ceramics, which are promising in solving challenges posed by emerging technologies, shows grand difficulties because of the immense compositional space and complex local distortions. In this work, an accurate machine learning (ML) model built upon an ab initio database is developed to predict the mechanical properties and structural distortions of multicomponent transition metal carbides (MTMCs). The compositional space of MTMCs is thoroughly explored by the well-trained model. Combined with electronic and geometrical analysis, we show that the elemental adaptability to the rock-salt structure elegantly elucidates the mechanical characteristics of MTMCs, and such adaptability can be quantified by local lattice distortions. We further establish new design principles for high-strength MTMCs, and V–Nb–Ta-based MTMCs are recommended, which are validated by the present experiments. The proposed model and design philosophy pave a broad avenue for the rational design of MTMCs with exceptional properties.

Separation of plant protection products from complex aqueous bodies using carbon-mineral composites incorporated with double metals (Ni/Mn or Ni/Fe)

Due to the extensive application of pesticides and their hazardous effects on organisms, there is an urgent need to remove them effectively from wastewater. Metal-incorporated carbon-mineral composites (Ni/Mn-CMC and Ni/Fe-CMC) described in this paper can certainly be applied for this purpose. They were synthesized by combining mechanochemical and pyrolytic processes and their physicochemical properties were investigated using numerous methods (SEM-EDS, N2 adsorption/desorption, XRD, surface charge, FTIR). Adsorption capacity towards diuron and carboxin with and without impurities commonly detected in natural ecosystems, cadmium ions or arsenite, was measured. The obtained results indicated that Ni/Fe-CMC is more efficient adsorbent of pesticides due to its well-developed surface. It was able to bind 158.34 mg g−1 of diuron and 133.58 mg g−1 of carboxin in the solutions, where only one pesticide was present. In turn, these values for the Ni/Mn-CMC sample were 126.49 mg g−1 and 102.08 mg g−1, respectively. It should be noted that the composites maintained their high adsorption capacity in the multicomponent solutions, i.e., containing both pesticide and metal ions. Then, the maximum reduction in pesticide adsorption was only 8.36. Ni/Mn-CMC and Ni/Fe-CMC were successfully regenerated with ethanol without changing their structure and adsorption capacity. Also, the extracts from investigated materials did not have negative impact on plant growth. This confirmed suitability of carbon-mineral composites for repeated multiple use without toxic effects to organisms.

Design parameters for fixed bed column of biosorbent developed from Syagrus romanzoffiana for the removal of mono and multicomponent metallic ions

A biosorbent produced from Jerivá coconut (Syagrus romanzoffiana) was utilized for removal of Cd2+, Cu2+, Ni2+, and Zn2+ ions in both single and multi-component systems. Adsorption equilibrium batch tests indicated that the Langmuir model best represented the adsorption of both mono and multi-component metal ions, with the multi-component adsorption classified as antagonistic. Among the desorbing solvents tested, 0.1 M H₂SO₄ was the most effective, achieving recovery efficiencies of 98.2 % for Cu2+, 77.9 % for Zn2+, 69.9 % for Cd2+, and 29.4 % for Ni2+. Continuous system tests were performed with an initial concentration of 25 mg L−1 for each metal in the single-component setup and a total concentration of 100 mg L−1 in the multi-component mixture. To evaluate the biosorbent's efficiency in adsorbate recovery, 4 cycles of adsorption-desorption were conducted in a fixed-bed column, revealing a gradual decrease in desorption efficiency over successive cycles. The biosorbent desorbed all four metal ions within approximately 40 min. Cu2+ was the most desorbed ion (193.1 mg L−1), followed by Cd2+ (98.6 mg L−1), Zn2+ (66.2 mg L−1), and Ni2+ (51.7 mg L−1). The operational parameters of the fixed-bed column demonstrated good adsorption performance after column regeneration.

Porous hollow sphere structure PrFeO3 as an efficient sensing material for n-butanol detection

N-butanol is a harmful volatile gas, so creating an appropriate n-butanol sensor is critical for preserving human health and the manufacturing environment. In contrast to single metal oxide semiconductors, multicomponent metal oxides, especially perovskite ternary metal oxides with the ABO3 structure, exhibit significant potential for development owing to their precise structures and diverse physicochemical properties. In this paper, three-dimensional porous hollow spheres PrFeO3 were synthesized by combining air annealing and hydrothermal techniques. The crystal structure, surface composition, chemical state, and morphology of PrFeO3 materials were evaluated using several kinds of characterization approaches. The gas sensitivity of PrFeO3 materials was also thoroughly explored. The results show that at the optimal working temperature of 280 ℃, the PrFeO3 material excels in n-butanol gas sensing, with a response of 85 for 100 ppm n-butanol. Additionally, the sensor demonstrates high selectivity for n-butanol gases, low concentration detection capability, outstanding repeatability, rapid reaction recovery time (18 s/13 s), long-term stability, and exceptional reproducibility. The unique morphology and high oxygen vacancy content of PrFeO3 provide numerous active sites on its surface, promoting the adsorption and desorption of n-butanol gas molecules and enhancing its gas-sensitive properties.

Powstawanie polifazowej asamblaży minerałów z grupy platynowców w masywie dunitowo-szonkinitowym Inagli w Aldan Shield na platformie syberyjskiej

The Inagli massif is a concentric-zonal ring massif consisting of a dunite core bordered by a sequential series of peridotites, pyroxenites and shonkinites. In dunites, there are densely disseminated accumulations of chromspinelides, as well as schlieren and veined particles of massive chromitites, to which polyphase growths of platinum-group minerals (PGM) are confined. The Inagli intrusive, like the well-known Konder massif, belongs to an independent "Aldan" type of platinum-bearing deposits. The Aldan type of ring intrusions is a platform analogue of the "Ural-Alaskan" zonal dunite-gabbro massifs of orogenic regions. In placers, dunites and chromitites of the Inagli massif, PGM are mainly represented by isoferroplatinum (Pt3Fe) with an admixture of iridium up to 8 wt %. In isoferroplatinum, symplektitic iridium particles and small inclusions of osmium, laurite, ehrlichmanite, malanite, as well as other sulfides and arsenides of platinum-group elements (PGE) are often observed. The bulk composition of such polymineral aggregates can be calculated based on the volume ratios and chemical composition of individual phases. The results obtained in this way show that the compositions of the initial polycomponent solid solutions vary from Pt-Ir-Fe to Ir-Os-Ru-Rh-Pt-Pd-Fe alloys. Polycomponent homogeneous solid solutions, which composition gradually changes from Ru-Rh-Ir-Os minerals to Fe-Pt alloys, are known in the Witwatersrand placers. A similar series of solid solutions of PGE is identified in the placers of the Guli massif on the Siberian platform. Unlike the placers of the Witwatersrand and Guli massif, where PGM are mainly represented by Os-Ir alloys, Inagli minerals have mainly a Pt-Ir-Fe composition with a low proportion of Os. The structures of most natural polyphase PGM aggregates are similar to those of artificial alloys, therefore, the former are also products of crystallization of multicomponent metal melts and their subsequent solid-phase transformations. The limits of solubility between PGE differ significantly, therefore, depending on the initial composition of metal alloys, both polycomponent solid solutions and polymineral aggregates can be formed. Based on the analysis of combined double and triple diagrams of PGE systems, the author considers possible ways of evolution of phase transformations of alloys of different composition.

Controllable preparation of metal oxide nanoparticles and Ni/CeO2 catalysts by microdroplets extraction and separation technology in mini-channel

The microreactor coupled mini-channel microdroplets extraction and separation technology (MES) was developed by adding polyvinyl alcohol (PVA) into microdroplets, realizing the controllable synthesis of a series of mono-component and multi-component metal oxide nano particles (MONPs). A double-layer surfactant structure composed of Span20 (oil phase surfactant) and PVA (water phase surfactant) was designed as a barrier to intercept and collect the precipitated salt at the microdroplet interface, the addition of PVA reduces the loss of salt components during the extraction process from 41.7 wt% to 1.1 wt%. The size control of mono-component MONPs (CuO, Co3O4, and NiO) was achieved using MES method. Furthermore, in the application direction of preparing multi-component MONPs, the advantages of MES in preparing multi-component catalysts (Ni/CeO2) were verified. TEM, XRD, H2-TPR, CO2-TPD, XPS, BET et al. characterizations have shown that Ni entered the lattice of CeO2 during precipitation to form a Ni-O-Ce solid solution and was therefore highly dispersed in CeO2. Ni/CeO2-MES showed high CO2 conversion and CO selectivity in reverse water gas shift (RWGS) testing compared to Ni/CeO2 catalysts prepared by impregnation method which has excellent thermal stability and can maintain over 99 % CO selectivity even after 50 h of reaction at 600 °C. The MES method was proved to be an efficient synthesis technology for MONPs and can be extended to a variety of metal oxides catalysts.

Effect of Pd content in multi-component alloys [CoFeNi]Pdx on their behavior in hydrocarbon-containing atmosphere

Multicomponent metal systems attract growing interest today, especially as catalysts for various processes. In the present work, a series of [CoFeNi]Pdx alloys (equal atomic content of base metals) doped with palladium in the amount of 0–10 at.% were synthesized via thermolysis of multicomponent precursors. The resulting [CoFeNi]Pdx alloys were found to be single-phase solid solutions with a fcc structure represented by agglomerates of grains fused. The performance of the alloys was explored in a mixture of saturated hydrocarbons (C2–C4) within the temperature range of 600–675 °C. As a result of interaction with the reaction mixture, spontaneous disintegration of the alloys containing above 2 at.% Pd occurs with the formation of dispersed particles responsible for the catalytic growth of carbon nanofibers (CNF). The dependence of the productivity of the [CoFeNi]Pdx alloys towards CNFs on the x parameter was studied. The highest CNF yield (YC = 25–46 g/gcat, 30 min) was achieved at an optimal Pd concentration of 8 at.% within the entire temperature range. According to TEM and EDX data, regardless of the reaction temperature and Pd concentration in the alloy, the catalyst particles have the same composition as defined at the synthesis of the alloys. The resulting CoFeNiPd@CNF composite can be considered as a catalyst for other heterogeneous catalysis processes.

Design of microfluidic fluorescent sensor arrays for real-time and synchronously visualized detection of multi-component heavy metal ions

The majority of the environmental heavy metal ions exist in the form of multi-components, and the current single-to-single rapid detection methods are unable to meet the needs of simultaneous multi-component detection. Here, we have designed a microfluidic fluorescence sensor array by combining microfluidic sensing and organic fluorescent switches for the real-time and simultaneous visual detection of multi-component heavy metal ions. A series of “light-up” organic molecular probes was designed and synthesized, exhibiting a strong ability to bind heavy metal ions and resulting in the opening of probe fluorescence. Meanwhile, we design microfluidic sensor plate, the patterned path of the microfluidic plate has drainage channel wall and 2.70° downward slope, which can enable the samples to quickly reach the detection area. By loading organic molecular probes into the detection area, the microfluidic sensor array achieves simultaneous detection of four heavy metal ions. Combined with intelligent terminal, read and analyze the RGB color mode (RGB) results of detection, obtain quantitative information. The microfluidic fluorescence sensor array developed here can meet the requirements for in situ and semi-quantitative detection of a range of heavy metal ions with a low detection limit, fast reaction speed, and without the need for pretreatment. It represents a novel engineering technology approach for real-time detection of multi-components in the environment.

Atmospheric oxygen plasma-activated novel multicomponent transition metal phosphides (MnCoCu–P) for enhanced electrocatalytic water splitting to green hydrogen production: A universal catalyst across various pH electrolytes

Hydrogen (H2) is widely acknowledged as a promising, sustainable, and environmentally friendly energy carrier, offering numerous environmental benefits over conventional fossil fuels. However, the advancement of this technology is severely hindered by the scarcity of effective and robust catalysts for hydrogen evolution (HER) and oxygen evolution (OER) reactions activity. This study marks the inaugural fabrication of a hybrid tri-metallic electrocatalyst, termed MnCoCu–P, through hydrothermal synthesis. Subsequently, the catalyst undergoes atmospheric O2 plasma surface activation, aiming to amplify the efficiency of water splitting. The novel atmospheric O2 plasma-activated MnCoCu–P electrode outperforms the reported classic metal phosphides, and it outperformed the compared commercial Pt/C and RuO2 benchmark catalysts with outstanding performances of 0.488 and 1.20 V towards HER and OER at 1000 mA/cm2, respectively. Additionally, the MnCoCu–P (5 min) catalyst Faradic efficiency was calculated under alkaline conditions in 1.0 M KOH, and both the produced gas H2 and O2 match the theoretical and experimental calculated values well, indicating a high efficiency of almost 100%. In the 2-E system, MnCoCu–P (5 min)‖MnCoCu–P (5 min) demonstrated remarkable performance by attaining a current density of 1000 mA/cm2 at low total cell voltages of 1.93 V and outperforming the benchmark Pt/C‖RuO2 electrode system. On the other hand, the MnCoCu–P electrode possesses excellent activity under industrial conditions at 6.0 M @ 60 °C exhibited 1.89 V at 1000 mA/cm2 and performs well in natural water systems. Moreover, the 5 min O2 plasma-treated MnCoCu–P‖MnCoCu–P electrodes showed improved activity in all the pH solutions which makes it one of the potential candidates for commercial application in the future.

A facile high-efficiency preparation strategy for Al-containing multi-component boride microcrystals with superior comprehensive performance

Multi-component transition group metal borides (MMB2) have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics. Most of the current methods, however, are complicated and time-consuming, the mass production remains a challenge. Herein, we proposed a new high-efficiency strategy for synthesis of MMB2 using molten aluminum as the medium for the first time. The prepared Al-containing multi-component borides (TiZrHfNbTa)B2 microcrystals had a homogeneous composition with a hexagonal AlB2 structure and ultra-high hardness value of ∼35.3 GPa, which was much higher than data reported in the literature and the rule of mixture estimations. Furthermore, combined with the First-principles calculation results, we found that the Poisson's ratio (v) values exhibit a clearly ascending trend from 0.17 at VEC = 3.5 to 0.18 at VEC = 3.4, then to 0.201 at VEC = 3.2 with the increasing of Al content. This indicates that the intrinsic toughness of multi-component boride microcrystals is obviously enhanced by the trace-doped Al elements. Besides, the fabricated Al-containing multi-component boride microcrystals have superior oxidation activation energy and structural stability. The enhanced oxidation resistance is mainly attributed to the formation of a protective Al2O3 oxide layer and the lattice distortion, both of which lead to sluggish diffusion of O2. These findings propose a new unexplored avenue for the fabrication of MMB2 materials with superior comprehensive performance including ultra-hardness and intrinsically improved thermo-mechanical properties.

Improving hydrogen isotope permeation resistance of (TiVAlCrZr)O multi-component metal oxide coating by O+ Ion implantation

Oxygen vacancy can greatly affect the performance of metal oxide to hydrogen isotope permeation resistance. In this work, we report a new strategy to improve the permeation resistance by oxygen ion implantation. A (TiVAlCrZr)O multi-component metal oxide film was prepared as a tritium permeation barrier on a 316 L substrate by RF magnetron sputtering deposition, and then implanted by oxygen ions to fill the oxygen vacancies inside. The grazing incidence X-rays (GIXRD) analysis showed that the pristine and the oxygen-implanted coatings were in an amorphous phase. The deuterium permeation resistance of the four coatings was tested by a gas-driven device. The result showed that the pristine coating had a permeation reduction factor (PRF) of 5,610 at 500 °C, while there was a 13.6 times of increase in PRF with an oxygen concentration of 11.4 at.% with the best-reported value of 76,500, and more oxygen ions implanted, the better the deuterium permeation resistance of the coating. The GIXRD showed that after the test the pristine coating remained amorphous, while some crystals were formed in the oxygen-implanted coating with an oxygen concentration of 11.4 at.%. Oxygen ion implantation enhanced the deuterium permeation resistance by filling the oxygen vacancies and forming of more stable state of amorphous multi-component metal oxide, which is expected to be a new type of deuterium permeation barrier.