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The influence of Mo on the coarsening behavior of L1 2 -precipitates in chemically complex alloys (CCAs) was thoroughly investigated. Mo addition significantly impacted the morphology, misfit, and microstructural stability of L1 2 -precipitates during aging treatment. Mo incorporation into the B sublattice sites of L1 2 -precipitates (along with Al and Ti) increased their volume fraction and solvus temperature. It also weakened the segregation of solutes between the FCC-matrix and L1 2 -precipitates, resulting in reduced misfit. However, during the aging processing, the misfits in all three CCAs continuously increased. Quantitative analysis revealed that a misfit of approximately 0.5 % yielded cubic morphology of L1 2 -precipitate for CCAs with positive misfits. Further coarsening kinetics studies unveiled a transition from initial matrix-diffusion controlled coarsening to interface-reaction controlled coarsening. Notably, Mo addition prolonged the matrix-diffusion controlled stage and delayed the transition to interface-reaction controlled coarsening. These findings provide valuable insights that can guide future alloy design and heat treatment strategies to optimize the high-temperature structural performance of L1 2 -precipitate CCAs. • The relationship bewteen lattice misfits and L1 2 -precipitates morphology of chemically complex alloys is established. • Incorporation of Mo into L1 2 B-sites increases precipitate volume fraction and solvus temperature. • Mo prolongs matrix-diffusion controlled coarsening of L1 2 -precipitates, delaying transition to interface-reaction control. [ABSTRACT FROM AUTHOR]

Although molybdenum carbide (Mo x C) has emerged as an effective absorber of electromagnetic (EM) waves, its practical application is hindered by impedance mismatch and single loss mechanism. Herein, we developed a one-step method for creating NaCl template precursors assembled with ZIF-67 to produce porous multiple components of Mo x C composites. The Mo x C-Co/C composites exhibit a minimum reflection loss (RL min) of −59.69 dB with a bandwidth of 3.12 GHz at a thickness of 1.50 mm. The RL min reaches −71.39 dB with a bandwidth of 4.08 GHz at a thickness of 2.09 mm. The flower-like Mo x C-Co/C composites are capable of improving impedance matching and offering multiple loss mechanisms such as interfacial polarization, dipolar polarization, conductive loss and magnetic loss, resulting in enhanced EM wave absorption. Thus, our work featured a simple strategy to provide a unique insight into fabricating high-performance EM wave absorbers on molybdenum carbon basis. [Display omitted] • Mo x C-Co/C composites was synthesized by one-step pyrolysis. • The resulting composites has a porous flower-like microstructure. • Metal cobalt improves the impedance matching and introduces magnetic losses. • Mo x C-Co/C composites showed an RL min of −71.39 dB with a bandwidth of 4.08 GHz at 2.09 mm. [ABSTRACT FROM AUTHOR]

High-efficiency catalysts are required for the oxygen reduction reaction (ORR) in fuel cell applications. Herein, we present a novel hybrid material that is based on uniformly deposited nanoscale molybdenum phosphide (Mo x P y) nanoparticles on the structure of graphene nanolayers doped with phosphorus atoms (PG). With a positive onset potential of only −0.046 V and a half-wave potential value of roughly −0.17 V (vs. Ag/AgCl), the obtained hybrid showed good catalytic activity for ORR in 0.1 M KOH electrolyte. It also demonstrated remarkable durability for oxygen reduction reaction in 0.1 M KOH electrolyte when compared to state-of-the-art Pt/C material. The excellent ORR performance can be correlated to the development of a highly conducting microporous structure with highly active sites, which in turn encourages optimal adsorption of intermediates during the ORR process and thus enhances the catalytic process. This work can open a new path for the growth of promising highly efficient catalysts for affordable fuel cell applications. [Display omitted] • Uniform Mo x P y nanoparticles dispersed P-doped G was prepared by a facile route. • The hybrid offered high catalytic performance for ORR, close to Pt/C. • The synergistic effect from Mo x P y and P-doped Gr produced enhanced ORR performance. • The hybrid showed much better durability and methanol tolerance than Pt/C. [ABSTRACT FROM AUTHOR]

Molybdenum-rhenium alloys has a low recrystallization temperature and insufficient high temperature strength, making it unable to serve as structural parts for a long time in high temperature environments above 1300 ℃ for a long time. ZrO 2 dispersion strengthened Mo-Re alloy was prepared by liquid-liquid doping combined with hydrogen reduction. The morphology and distribution of ZrO 2 were adjusted by liquid-liquid doping-coprecipitation-codeposition technology, with ZrO 2 dispersed in the grain of Mo-Re alloy to refine the grain. The average grain size is reduced from 14.99 μm to 8.41 μm, and the yield strength is 539 MPa, representing an increase of 16.2 %. When the strain is 43 %, the high temperature compression performance at 1400 ℃ reaches 214 MPa, which is 28.1 % higher than that of Mo-Re. The enhanced performance is attributed to the dislocation pinning of ZrO 2 and the formation of a semi-conformal interface between ZrO 2 and the matrix, which addresses the issue of weak interfacial bonding to reinforce Mo-Re alloys. It provides a new idea for the design of Mo-Re alloys structural components such as space fission reactors fuel cladding in ultra-high temperature environment. • ZrO 2 doped Mo-based alloys was prepared by liquid-liquid doping method. • Compressive strength of Mo-5Re-1ZrO 2 alloys increases 28.1 % in comparison with Mo-5Re. • ZrO 2 doped Mo-based alloys has good high temperature strength. • Provides a hydrothermal synthesis process which can be industrially applied. [ABSTRACT FROM AUTHOR]

Vacancy defect engineering is an effective strategy for improving photocatalytic activity, but controlling surface vacancies precisely remains a challenge. In this study, MoO 2 /Mo doped BiOCl (Mo-BiOCl) composites enriched with oxygen vacancies (OVs) were prepared by a facile defect engineering strategy with MoO 2 hollow spheres as a precursor and molybdenum sources, where the slowly released Mo4+ ions in the reaction system resulted in the tailored formation of Mo-BiOCl. The optimized MoO 2 /Mo-BiOCl composite (BOM-3) demonstrated significantly improved photocatalytic degradation efficiency for Tetracycline hydrochloride (TC) under visible light, with an apparent rate constant (k) 4.7 and 120 times higher than that of BiOCl and MoO 2 , respectively. The enhanced photocatalytic activity of BOM-3 can be attributed to the presence of abundant OVs, which extend the light response range by creating intermediate defect level from OVs. Additionally, the formation of ohmic heterojunction between Mo-BiOCl and MoO 2 with close interface contacts facilitates rapid separation of interfacial charge carries and efficient migration of photogenerated electrons from Mo-BiOCl to MoO 2. The possible degradation pathway of TC using BOM-3 is proposed, and toxicity evaluation indicates that most intermediates have lower toxicity than TC. This work presents a straightforward approach for improving photocatalytic antibiotic degradation through the construction of a novel Ohmic-junction with tuned surface OVs. [Display omitted] • MoO 2 /Mo-BiOCl with rich oxygen vacancies (OVs) were fabricated by a defect strategy. • MoO 2 hollow spheres were applied as both precursor and molybdenum sources. • The existence of OVs accounts for the enlarged light response range. • The Ohmic junction enables the effective migration of e– from Mo-BiOCl to MoO 2. • TC degradation rate of the optimized sample is 4.7 and 120 times that of BiOCl and MoO 2. [ABSTRACT FROM AUTHOR]

In recent years, an increase in cardiovascular diseases (CVD) has been observed, constituting a global health concern, owing to a steady escalation in patient numbers. For pro-long-life services in patients, the mechanical properties, biocompatibility, and degradation behaviors of metallic vascular stents should be significantly considered during the design and manufacturing progress. In particular, biodegradable metal-based vascular stents offer initial mechanical support for cardiovascular lesions and self-degradation during vascular remodeling, thereby obviating the necessity for subsequent surgeries. Biodegradable metallic vascular stents are regarded as a prominent direction for the future development of biodegradable vascular stents (BVS), owing to their distinctive capacity for spontaneous degradation and their superior mechanical properties, which confer significant benefits upon a broader demographic afflicted by cardiovascular disease. Currently, magnesium (Mg), iron (Fe), and zinc (Zn)-based alloys are the focus of extensive research in the field of cardiovascular biodegradable materials. This paper is dedicated to delineating the benefits and limitations of three metal alloys in cardiovascular stent applications, focusing on their mechanical performance and degradation characteristics. Furthermore, a discussion on their performance within in vitro experiments, animal trials, and clinical translation is encompassed. The performance evaluation of a prospective novel biodegradable material, molybdenum (Mo), is elucidated. [ABSTRACT FROM AUTHOR]

As the EV and ESS markets expand, there is a growing interest in LiFe x Mn 1-x PO 4 (LFMP) cathode materials amidst the increasing demand for LIBs. The LFMP cathode material is cost-effective and structurally stable; however, it has the drawback of low conductivity. Therefore, the development of an LFMP cathode material with high ionic/electronic conductivity is essential for high-stability and high-C-rate LIB applications. We propose a carbon-coated LFMP cathode material with Mo placed at the Fe and Mn sites. The samples were synthesized using a solvothermal method. Mo contributes to enhanced Li-ion diffusion and charge transfer rates. The XRD Rietveld refinement results showed elongated Li–O bonds within the Mo-doped LFMP/C, which accelerated the Li+ ion diffusion. Through SEM, TEM–EDS mapping, and XPS analysis we have confirmed the properties and morphology of the material. The electrochemical evaluation of the material was conducted using galvanostatic charge-discharge, CV, and EIS methods. Based on these tests, Mo incorporation not only increased the capacity but also enhanced the rate performance, reduced the voltage polarization, and improved the lithium-ion diffusion coefficient. Based on the 3.7 V additional plateau, which is attributed to the sluggish kinetics of Mn3+, Mo6+ played a role in enhancing the kinetic behavior of Mn3+. Low-temperature performance tests demonstrated that the Mo-doped samples exhibited high energy density, cycle retention, and superior ionic conductivity. In summary, an appropriate amount of Mo doping is effective for improving the electrochemical performance of LFMP, making it a promising cathode material. [Display omitted] • Mo-doped LFMP/C was prepared by employing a solvothermal method. • Mo ion-doping was beneficial for enhancing both ionic and electronic conductivity. • Mo-1 exhibited the most outstanding rate capability and cyclability. • Enhanced conductivity resulted in excellent low-temperature characteristics. [ABSTRACT FROM AUTHOR]

The characteristic of the γ′ strengthening phase plays a crucial role in the development of high performance nickel-based superalloys, which is strongly dependent on the kinetic behavior of γ′ precipitation. Herein, the precipitation kinetics of the nanoscale γ′ phase in Ni–10 Al–8.5 Cr– x Mo at% (x = 2, 3, and 4) quaternary alloys aged at 1073 K are investigated using CALPHAD-assisted phase field simulations. Our calculations show that the higher Mo content and lower aging temperatures delay the growth and coarsening kinetics of the γ′ phase, which can be attributed to the decrease of Al chemical mobility. Moreover, although Mo is a γ–stabilized element, previous experiments, thermodynamic calculations, and our simulations all indicate that the γ′ volume fraction increases abnormally with increasing Mo concentration in Ni–Al–Cr–Mo quaternary alloys, which is attributed to Mo occupying the Al sites of γ′-Ni 3 Al and the elemental partitioning behaviors between the γ matrix and the γ′ phase. In addition, Mo is a potential element to reduce the content of Re and W elements in nickel-based superalloys because of its lower density and stronger solid solution strengthening effect in the γ matrix. Our work can guide the design and development of lightweight nickel-based superalloys with superior microstructural stability and mechanical properties for engineering applications. • Precipitation kinetics of γ′ phase in Ni–Al–Cr–Mo alloys were quantitatively simulated. • The role of Mo concentration on γ′ coarsening kinetic was revealed. • The compositional evolution of γ matrix and γ′ precipitate was clarified. • The potential of Mo to reduce the content of W and Re elements was demonstrated. • The effect of aging temperatures on γ′ precipitation kinetics was studied. [ABSTRACT FROM AUTHOR]

Perovskite (ABO 3) and ruddlesden-popper (A 2 BO 4) oxides are typical mixed conducting ceramic membrane materials for oxygen separation from air. In particular, ruddlesden-popper (RP) membrane display high CO 2 resistance despite their relative low oxygen permeation flux compared to perovskite oxide membranes. Element-doping is an important method to improve the oxygen permeability. In this work, the mechanism of oxygen transfer process through one RP ceramic La 2 Ni 1-x Mo x O 4+δ (x = 0, 0.025, 0.05, 0.1, 0.2) membranes was investigated. An optimum doping level (x = 0.05) in La 2 Ni 1-x Mo x O 4+δ was found. The optimized composition of La 2 Ni 0.95 Mo 0.05 O 4+δ membrane could not only improve surface oxygen exchange reactions, but also promote oxygen ion bulk diffusion through the dense layer. The maximum oxygen flux of La 2 Ni 0.95 Mo 0.05 O 4+δ membrane reached 3.27 mL min−1 cm−2 at 1000 °C. Furthermore, La 2 Ni 0.95 Mo 0.05 O 4+δ membrane high stability in CO 2 atmosphere. When sweeping gas was switched from helium to pure CO 2 , the oxygen fluxes were only reduced by 5% and stabilized at 2.75 mL min−1 cm−2 at 950 °C. Our results highlight the efficiency of Mo-doping strategy to simultaneously improve the oxygen permeability and stability of A 2 BO 4+δ -type oxide membranes. • The influences of the Mo dosage inside La 2 NiO 4+δ system on the oxygen permeability are investigated. • La 2 Ni 0.95 Mo 0.05 O 4+δ with orthorhombic structure displays the best oxygen permeability. • La 2 Ni 0.95 Mo 0.05 O 4+δ displays great CO 2 -resistance with oxygen permeation flux of 2.75 mLmin−1cm−2 at 950 °C swpet by CO 2. [ABSTRACT FROM AUTHOR]

Homogeneously dispersed Mo 2 C nanoparticles onto nitrogen-doped carbon nanotube - reduced graphene oxide support (Mo 2 C/CNT-RGO) were prepared by a modified urea glass route. Simply heating an ethanol slurry of MoCl 5 , urea, CNT, and graphene oxide at 750 °C under nitrogen atmosphere uniformly distributed 8 nm Mo 2 C nanoparticles in the nitrogen-doped CNT-RGO support. The resultant Mo 2 C/CNT-RGO exhibited markedly improved electrochemical performance for hydrogen evolution reaction (HER) compared to similarly prepared Mo 2 C/CNT, Mo 2 C/RGO, and bare Mo 2 C. Enhanced Mo 2 C/CNT-RGO performance could originate from the synergy between Mo 2 C nanoparticles with high HER activity and N-doped CNT-RGO support providing large surface area and high electrical conductivity. Image 1 • A simple synthesis of nanostructured Mo 2 C/CNT-RGO composite is proposed. • Carbide formation, GO reduction, and N-doping are simultaneously achieved. • Mo 2 C/CNT-RGO is used as a catalyst for hydrogen evolution reaction (HER). • Mo 2 C/CNT-RGO shows high activity and stability for HER under alkaline media. • Unique CNT-RGO heterostructure helps to enhance the HER activity. [ABSTRACT FROM AUTHOR]

Thermo-mechanical processing of uranium-10 wt% molybdenum (U-10Mo) alloy fuel plates with a zirconium (Zr) interlayer leads to microstructure changes at fuel/interlayer interfaces. Secondary phases formed at this interface are particularly important to interfacial bond strength, process optimization, and maintaining structural integrity of the fuel plates during irradiation. In this work, we determined the phases and phase transformation products occurring at the interface of the U-10Mo fuel and Zr interlayer when fuel plates are subjected to short and long hot isostatic pressing (HIP) cycles. Interfacial morphology, crystal structure and composition of phases formed, and relative hardness across the U-10Mo/Zr interfaces were studied using a multi-length scale, multi-modal characterization approach involving electron microscopy, atom probe tomography, and atomic force microscopy. Results highlight that the extent of phase transformations, secondary phase formation, and hardness variability across interfaces can be controlled by modifying processing parameters. In addition, phases formed at U-10Mo/Zr interfaces are similar for both HIP process conditions, however, phase distribution, interface thickness, and relative hardness vary significantly. The extent of the discontinuous precipitation reaction leading to α -U formation is also impacted by temperature and pressure in the HIP step; greater time at elevated temperature/pressure increases extent of the DP reaction. • HIP cycle length impacts U-10Mo fuel/Zr interlayer interface thickness, distribution of secondary phases, and extent of phase transformation. • TEM and APT identify several phases at U-10Mo/Zr interfaces: α -U, γ -UMo, γ ′ -U 2 Mo, Mo 2 Zr, (U 0.66 Mo 0.33)Zr 2 , ZrC, and a mixed Zr-U oxide. • AFM reveals variability in hardness across U-10Mo/Zr interfaces can be controlled through modified processing parameters. [ABSTRACT FROM AUTHOR]

In this paper, a new sensor for methane detection based on vanadium dioxide (VO 2)-molybdenum telluride (MoTe 2) nanocomposites is reported for the first time. The VO 2 layered structure and MoTe 2 silver ear like structure were prepared using a hydrothermal method. The morphology, elemental composition, and valence states of VO 2 -MoTe 2 composites were investigated through transmission electron microscope (TEM), electron microscope (SEM), scanning X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The characterization results proved the successful synthesis of the composites. A series of tests were conducted on the methane gas sensing performance of VO 2 -MoTe 2 sensors at room temperature by building a gas testing platform. The results show that the sensor has outstanding gas sensing performance for methane under the interference of various gases, such as high sensitivity, fast response/recovery, selectivity, good repeatability and stability. The gas sensing mechanism of VO 2 -MoTe 2 nanocomposite sensors for enhancing methane performance was discussed in detail through characterization and testing results. The potential sensing mechanism of the sensor for methane can be attributed to the heterojunction and synergistic effect formed between p-type VO 2 and n-type MoTe 2. • The tremella like MoTe 2 nanoflowers modified VO 2 nanoflakes were synthesized by hydrothermal method. • MoTe 2 doped VO 2 nanocomposite sensor showed enhanced methane sensing performance at room temperature. • The enhanced sensing properties were mainly attributed to the formation of p-n heterojunction. [ABSTRACT FROM AUTHOR]

The oxidation behavior of nanostructured Y-Zr-O complex oxide dispersion-strengthened Mo alloys was investigated using the thermogravimetric analysis in synthetic air at 300 °C, 600 °C, and 700 °C for 2 h, respectively. The Mo alloys have a higher weight gain than pure Mo, indicating a deterioration in oxidation resistance, which is derived from the ultrafine grain structure by providing more boundaries for the diffusion of oxygen and accelerating the oxidation rate. Whereas a low weight gain followed by a slow rate of weight loss is observed with increasing Zr addition, revealing the oxidation resistance is improved as the dissolved Zr concentration in the matrix increases. The dissolved Y and Zr promote the formation of the Y-Zr-Mo-O phase in the outer MoO 3 layer, which suppresses the formation and volatilization of MoO 3. • A deterioration in the oxidation resistance of Mo alloys is observed owing to the ultrafine-grained structure. • The oxidation resistance of Mo alloys is improved by increasing the dissolved Zr concentration. • The dissolved Y and Zr promote the formation of Y-Zr-Mo-O phase, which suppresses the formation and volatilization of MoO 3. [ABSTRACT FROM AUTHOR]

In this study, the microwave-assisted self-propagation high-temperature synthesis (SHS) technique was utilized to successfully synthesize the Nistelle super C commercial alloy with the chemical composition of Ni 59 Cr 23 Mo 18. The precursors used for this purpose were NiO, Cr 2 O 3 , and MoO 3 oxide compounds. The thermodynamicall calculations were carried out by the Factsage software. The synthesized alloys' chemical composition, phase, and microstructure were evaluated by induction-coupled plasma, X-ray diffraction, optical microscopy, and scanning electron microscopy. The findings revealed considerable residual silicon in the final product due to using Si as the reducing agent. The presence of residual Si in the chemical composition led to forming a eutectic Ni γ -FCC+ Mo 2 Ni 3 Si microstructure in the alloys produced by the alumino/silicothermic method. The high silicon content in the excess Al-containing sample led to forming of proeutectic Mo 2 Ni 3 Si phases with a petaloid morphology. Besides, this alloy displayed small islands of the interdendritic nickel silicide phase. Conversely, the aluminothermic sample showed a nearly single-phase structure with low amounts of the precipitates of chromium and molybdenum-rich phases. The phase diagram plotted for this sample indicated that the precipitates were probably TCP phases like σ and P. In all the samples, the segregation of Mo occurred significantly, while Cr was distributed almost uniformly in all regions. The formation of the Mo 2 Ni 3 Si intermetallic phase resulted in the significant segregation of Mo and depletion of the Niγ-FCC matrix from this element. However, the segregation of Mo was also observed near the grain boundaries in the single-phase sample. The results showed that the dissolution of the alloying elements, especially molybdenum, caused severe offset in some peaks of the Ni γ -FCC XRD pattern. • The presence of silicon led to the formation of intermetallic compounds. • Adding excess aluminum led to more residual silicon in the final product. • The aluminothermic sample has a Niγ -FCC structure, containing TCP phases. • Unlike chromium, molybdenum has a considerable tendency to segregation. [ABSTRACT FROM AUTHOR]

Tungsten trioxide (WO 3) films are of great interest due to their electronic properties which can be tuned by surface nanostructuring leading to enhanced efficiency for gas sensing, energy storage or electrochromic applications. Resistive heating of tungsten (W) filaments at pressures of few Pa in an oxygen O 2 atmosphere has already demonstrated its capability to form porous, micro/nano-structured, cheap and fast films making it suitable for industrial applications. This work presents stoichiometric WO 3 films produced by applying a current into a W filament for pressures in the range of 2–20 Pa. The increase of the pressure above 7.5 Pa led to amorphous WO 3 films with a newly filamentous morphology. As a function of the pressure, the work function (W F) of the films was determined in-vacuo by aims of Ultraviolet Photoelectron Spectroscopy (UPS). In addition to the high surface to volume ratio of the films, the W F exhibited an increase from 5.8 eV, for a conventional WO 3 film, to a maximum of 8.7 eV at 20 Pa. This change corresponds to an increase of the W F of about 50% compared to 5.8 eV making our films suitable for a large variety of applications. The highering of the W F is mainly induced by the change of morphology to filamentous structures, the defect induced by the amorphous structure and the nanometric size of the filaments leading to the confinement of the electrons in the valence band for our WO 3 films. Additionally, a change from p to n-type polarity is reported in-vacuo when increasing the pressure from 7.5 to 20 Pa with the formation of an intermediate band at around 0.8 eV below the Fermi level. Additionally, molybdenum trioxide (MoO 3) and vanadium pentoxide (V 2 O 5) filamentous films were deposited via the resistive evaporation technique in an O 2 atmosphere. Similarly, copper, aluminium and molybdenum wires were used, leading to the formation of islands having foam-like structures analogous to the WO 3. • Formation of stochiometric filamentous WO3 coatings by resistive heating evaporation technique. • Enhancement of the in-situ work function (W F) for filamentous coatings by 50conventional WO 3 films. • Capability to produce filamentous Mo, Al and Cu films. [ABSTRACT FROM AUTHOR]

Aluminum nitride (AlN) has been widely used in bandpass filters for wireless communication applications, but its low electromechanical coupling factor (k t 2 ) limits the bandwidth of the filter based on it. In this work, AlN alloys incorporated with various transition metals are theoretically studied, and Mo-alloy AlN (Mo x Al 1−x N) is predicted to be more prominent in improving k t 2 . Furthermore, the influence of Hubbard U correction on the k t 2 of Mo x Al 1−x N is discussed, and the correction is found to show a crucial role at a high x. The magnitude of k t 2 is more correlated with the piezoelectric stress constant e 33 , and both of them depend on the distribution of Mo atoms. The contribution of each atom to piezoelectric performance is described by an effective displacement-response internal-strain parameter Γ 33 in this work, which is generally proportional to internal parameter u and response of u to applied strain along the z -axis. The increase of k t 2 is ascribed to the Mo-induced larger u and Γ 33 , but the Mo dimer and line along the z-axis weaken the increase mechanism. To obtain a high k t 2 , it is better to alloy Mo atoms into more sublayers of AlN and with fewer Mo dimers and lines along the z -axis. The behavior that the Mo atoms distributed evenly in the xy plane is also beneficial. A high k t 2 of 37.8% is predicted in a special quasirandom configuration of Mo 0.167 Al 0.833 N, which might be the highest value reported to date for the AlN alloys. [Display omitted] • Mo-alloy AlN outperforms other alloys in enhancing the k t 2 of AlN. • A high k t 2 of 6.87 times that of pure AlN is predicted. • The magnitude of k t 2 depends on the distribution of Mo atoms in Mo x Al 1−x N. • Γ 33 is used for the first time to explain the contribution of each atom to k t 2 . [ABSTRACT FROM AUTHOR]

In this experiment, the nano-ZrO 2 particles reinforced molybdenum alloy with excellent mechanical properties were prepared through liquid-liquid doping process, and the comparison with TZM alloy prepared by solid-solid doping process was conducted. During the liquid-liquid doping process, the ZrO 2 particles ensured the dispersion of the second phase in alloy because they reached molecular-level uniformity, and the hydrothermal synthesis preparation process enabled the ZrO 2 particles in alloy to reach nanometer size level. In Mo-ZrO 2 alloy, the small and dispersed ZrO 2 can effectively block dislocation and passivation cracks; both the room temperature and high temperature performance of Mo-1.5 %ZrO 2 alloy was better than that of TZM alloy. Based on the hindered recrystallization process, improved recrystallization temperature, as well as enhanced recrystallization strength thanks to the alloy pinning effect of ZrO 2 , the maximum tensile stress of Mo-1.5 %ZrO 2 alloy at 1000 ℃ was about 14 % higher than pure molybdenum, and the maximum tensile stress of Mo-1.5 %ZrO 2 alloy at 1400 ℃ was at least 45 % higher than pure molybdenum. Quantitative analysis shows that the strengthening effect of the second phase was the best during the recrystallization process. [Display omitted] • In the experiment, the liquid-liquid doping process is applied to prepare nano-ZrO 2 particle-reinforced molybdenum alloy with excellent mechanical properties. • By means of liquid-liquid doped ZrO 2 particles, the molecular-level uniformity is realized, and the dispersion of the second phase in alloy is ensured. • The pinning effect of refined and dispersed ZrO 2 can effectively hinder the recrystallization process and improve the alloy recrystallization temperature as well as strength. [ABSTRACT FROM AUTHOR]

Lithium-sulfur batteries (LSBs) are appealing energy storage systems by virtue of the high theoretical energy density and abundant resources of sulfur. However, the sluggish redox reaction kinetics and shuttle effect of soluble lithium polysulfides (LiPSs) seriously restrict their practical applications. Searching for highly efficient and low cost electrocatalysts towards LiPSs conversion is one of the most promising approaches to relieve the shuttle effect and enhance the sulfur utilization. In this work, we first demonstrate the application of ternary iron molybdenum nitride hybridized with nitrogen-doped carbon, denoted as (Fe 0.81 Mo 0.19)MoN 2 /NC composite, as an advanced separator modifier to boost the bidirectional catalytic conversion of LiPSs. Impressively, the as-fabricated LSBs with (Fe 0.81 Mo 0.19)MoN 2 /NC modified separator display an ultrahigh initial discharge capacity of 1366.1 mAh g−1 at 0.1 C and still remains a high value of 809.1 mAh g−1 at a high rate of 4 C. Furthermore, a remarkable discharge capacity of 569.2 mAh g−1 is retained when cycling at a high rate of 1 C for 700 cycles (corresponding to a low attenuation rate of 0.065 % per cycle), indicating the good long-term cycling stability. The excellent performance could be attributed to the multiple advantages of high electrical conductivity, numerous active sites, strong adsorption ability and excellent catalytic activity, thereby effectively suppressing the shuttle effect of LiPSs. The present work indicates that the ternary transition metal nitrides could be promising separator modifiers for high-performance LSBs. [Display omitted] • Ternary iron molybdenum nitride and nitrogen-doped carbon composite is rationally synthesized. • The (Fe 0.81 Mo 0.19)MoN 2 /NC composite is employed as a separator modifier for lithium-sulfur batteries. • The (Fe 0.81 Mo 0.19)MoN 2 /NC composite can boost the bidirectional catalytic conversion of lithium polysulfides. • The lithium-sulfur batteries with (Fe 0.81 Mo 0.19)MoN 2 /NC modified separators display excellent performance. [ABSTRACT FROM AUTHOR]

Phase equilibria of the Mo-Y 2 O 3 -ZrO 2 -Zr section in the Mo-Y-Zr-O system at 1200 ℃ were studied for developing nanostructured Y-Zr-O complex oxide dispersion-strengthened Mo alloys and understanding the formation behavior of oxides. The evolution of intermetallic Mo 2 Zr and the powder composition of this Mo alloy during mechanical alloying (MA) were revealed. The results showed that the Mo-Y 2 O 3 -Zr section was confirmed by four kinds of two-phase regions (Mo) + αY 2 O 3 and (β Zr) + α Y 2 O 3 and three-phase regions (Mo) + α Y 2 O 3 + Mo 2 Zr and (β Zr) + α Y 2 O 3 + Mo 2 Zr. These three-phase equilibria were associated with the four-phase equilibria of (Mo) + α Y 2 O 3 + Mo 2 Zr + (α Zr) with a high concentration of O in (α Zr). During MA, Mo 2 Zr was dissolved in the Mo matrix, and the introduced excess O and ZrO 2 contaminants shifted alloy composition from Mo-Y 2 O 3 -Zr to Mo-Y 2 O 3 -ZrO 2. The Mo-Y 2 O 3 -ZrO 2 section was characterized by six kinds of two-phase regions Mo + β ZrO 2 , Mo + γ ZrO 2 , Mo + Zr 3 Y 4 O 12 , and Mo + α Y 2 O 3 , three-phase regions Mo + β ZrO 2 + γ ZrO 2 and Mo + γ ZrO 2 + Zr 3 Y 4 O 12. The established Mo-Y 2 O 3 -ZrO 2 -Zr phase diagram suggests that the presence of excess Zr and insufficient O can bring about the formation of brittle Mo 2 Zr and Zr phase, and the Y/Zr ratio strongly determines the type of Y-Zr-O precipitates in Mo alloys. • Phase equilibria of the Mo-Y 2 O 3 -ZrO 2 -Zr section in the Mo-Y-Zr-O system at 1200 ℃ were experimentally studied. • The introduced excess O and ZrO 2 contaminants shifted alloy composition from Mo-Y 2 O 3 -Zr to Mo-Y 2 O 3 -ZrO 2. • The Y/Zr ratio strongly determines the type of Y-Zr-O precipitates in Mo alloys. • The excess Zr and insufficient O can bring about the formation of Mo 2 Zr and Zr phases. [ABSTRACT FROM AUTHOR]

Crystal structure has an important effect on electrochemical performance. In this work, the molybdenum carbide/carbon hollow microtube (MoC/CHMT) composite is synthesized via carbonation of polydopamine encapsuled Mo-MOF material. Additionally, the crystal structure of molybdenum carbide in composite is controlled by adjusting the mass of dopamine in polymerization. The optimized MoC/CHMT shows the hollow microtubes morphology with the microtube diameter about 600–1100 nm and microtube wall thickness of 230–400 nm, constructed by small molybdenum carbide nanoparticles (about 1.2–1.5 nm) on the surface of nanoplates with thickness of ∼17 nm. Moreover, it could achieve a high specific capacitance of 513.5 F g−1 at a current density of 0.5 A g−1. The constructed YP50//MoC/CHMT device exhibits a maximum energy density of 17.5 Wh kg−1. [Display omitted] • The MoC/CHMT composite is synthesized via carbonation of polydopamine encapsuled Mo-MOF material. • The relationship between crystal structure of MoC/CHMT and electrochemical performance is investigated. • The optimized MoC/CHMT achieves a higher specific capacitance of 513.5 F g−1. [ABSTRACT FROM AUTHOR]

In the present contribution, we used the spray drying method for the preparation of molybdenum-based composite powders, which belong to an important class of high-temperature structural materials – oxide dispersion strengthened molybdenum alloys (ODS-Mo). Three types of materials were prepared via spray drying and subsequent steps of calcination and reduction, including undoped reference Mo, ODS-Mo doped with 1 wt% of La 2 O 3 , and ODS-Mo doped with 1 wt% of La 2 O 3 and 1 wt% of ZrO 2. The particular focus was given to precursor solution; specifically, the effects of type (aqueous or water-ethanol mixture) and chemical composition (the addition of La and Zr precursors) were studied in detail, which was rarely given attention in previous research. The morphological and microstructural changes of the particles during oxidation and reduction of sprayed-dried powders were extensively analysed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). The morphology and crystallinity of spray dried powders were controlled by the state of spraying precursor solution, i.e. homogeneous solution or particle suspension. Calcination at the temperatures of 500 °C and 650 °C produced spherical polycrystalline and slab-shaped monocrystalline MoO 3 oxide particles. Subsequent reductive treatment of transformed calcined powders into metal-based powders took place with efficiency that depended mainly on the type of spraying solution (aqueous solution or water-ethanol suspension) and its chemical composition, in which case, the addition of La and Zr precursors resulted in lower efficiency than the addition of La alone. In terms of powder particle size, homogeneity of alloying elements, and reduction efficiency, the powders produced from water-ethanol suspensions were clearly superior to those produced from aqueous solutions. • La and La-Zr doped Mo powders were produced by spray drying/calcination/reduction. • Spraying solution (aqueous vs. water-ethanol) affected microstructure of powder. • Calcination at 500/650 °C produced spherical/slab-shaped particle morphology. • Undoped and La-doped powders reduced more efficiently than La-Zr doped powder. • Powders dried from water-ethanol and calcined at 500 °C have optimal properties. [ABSTRACT FROM AUTHOR]

A high-performance hydrogen sulfide sensor is introduced in this paper. CuO/MoSe 2 nanocomposites were synthesized using a simple hydrothermal method, and the sensing properties of CuO/MoSe 2 composite films for H 2 S gas were investigated at 75 °C. The gas sensor test results revealed that the CuO/MoSe 2 composite membrane sensor outperforms the single material sensor in terms of response, response/recovery time, linearity, and long-term stability. The enhanced gas sensitivity of the CuO/MoSe 2 nanocomposite could be attributed to the synergistic effect of the two materials' p-p heterojunction. Using DFT simulation, it was also shown that the CuO/MoSe 2 composite sensor's ability to adsorb H 2 S is superior to that of CuO and MoSe 2 used alone. • The MoSe 2 nanowire modified by CuO nanowire was prepared by hydrothermal method. • The CuO/MoSe 2 composite sensor exhibits enhanced hydrogen sulfide sensing performance at lower temperatures. • The enhanced sensing properties were mainly attributed to the formation of p-p heterojunction. [ABSTRACT FROM AUTHOR]

Multi−component absorbers can improve microwave absorption performance by incorporating multiple loss mechanisms. However, many multi−component absorbers containing magnetic metal-based nanomaterials are unstable, owing to aggregation and oxidation of metal nanomaterials. In this work, (Fe 0.64 Ni 0.36 @C/Mo 2 C@C)@N − C composites were prepared by mixing nickel molybdate, potassium ferricyanide, and dopamine to form a precursor which was subsequently carbonized. The Fe 0.64 Ni 0.36 and Mo 2 C nanoparticles in the composites were stabilized by a thin graphitic carbon coating and uniformly dispersed throughout the N-C matrix. This unique structure provided abundant interfaces for microwave absorption, whilst also effectively inhibiting the aggregation and oxidation of the metal-containing phases. One of the prepared composites, (Fe 0.64 Ni 0.36 @C/Mo 2 C@C)@N − C− 3, possessed excellent microwave absorption properties, evidenced by a wide effective absorption bandwidth (EAB) of 5.7 GHz (11.9 −17.6 GHz) at 2.0 mm thickness, and the minimum reflection loss value (RL min) of − 37.5 dB at 11.92 GHz and 2.5 mm thickness (at a filling amount of 16.7%). • (Fe 0.64 Ni 0.36 @C/Mo 2 C@C)@N − C composite absorbers were successfully prepared. • The Fe 0.64 Ni 0.36 and Mo 2 C nanoparticles were stabilized by a thin graphitic carbon. •.The EAB reaches 5.7 GHz, and the RL min is -37.5 dB at 11.92 GHz. [ABSTRACT FROM AUTHOR]

MoSi 2 has a low density, high conductivity, and anti-fluorine structure. Therefore, we prepared MoSi 2 -modified LiNi 0.6 Co 0.1 Mn 0.3 O 2 (NCM613) materials by a solid-state method using the precursors of MoSi 2 and NCM613. Analysis using XRD, HRTEM, SEM and XPS reveals that a small amount of Mo from MoSi 2 was doped into the NCM613 lattice, and the rest MoSi 2 was coated on the material surface. DFT calculations show that Mo atom doping preferentially replaces Ni sites in the NCM613 transition metal layer to form more Ni2+. The capacity retention of the best modified sample NCM-0.5MoSi 2 is 74.1% (from 174.0 to 129.0 mAh·g−1) after 300 cycles at 1 C, while the pristine material NCM-0 is only 49.6% (from 171.5 to 85.1 mAh·g−1). Furthermore, the lithium-ion diffusion coefficient of NCM-0.5MoSi 2 is 3.44 × 10−12 cm2·s−1, higher than 2.73 × 10−12 cm2·s−1 of NCM-0. Improved electrochemistry results from Mo doping and MoSi 2 coating, where Mo doping expands the lattice parameters of NCM613 and MoSi 2 coating protects NCM613 from hydrofluoric acid (HF) corrosion. This work achieves the dual effect of Mo doping and MoSi 2 coating through the modifier MoSi 2 , and provides a reference scheme for the improvement of other cathode materials. [Display omitted] • MoSi 2 -modified NCM613 material was prepared by solid-state method. • Dual effects of Mo doping and MoSi 2 coating achieved by modifier MoSi 2. • XPS combined with DFT further studied the mechanism of Mo doping. • MoSi 2 coating plays a dual role of high conductivity and anti-fluorine structure. • The capacity retention of NCM-0.5MoSi 2 is 74.1% after 300 cycles at 1 C. [ABSTRACT FROM AUTHOR]

Two dimensional MoSe 2 mono and few layer were prepared by the atmospheric pressure chemical vapor deposition (CVD). It is essential to understand completely the growth and nucleation mechanism to improve the crystalline quality and size of two dimensional transition metal dichalcogenides materials using CVD. Three different types of MoSe 2 surface structure were identified for the different growth temperatures. By changing the growth temperatures, the concentration of MoO 3-x and Se vapor precursors vary which derive different nucleation mechanism. Low vapor concentration of reactants leads to mono and bi layer MoSe 2 due to 2D planar nucleation while higher concentration of reactants facilitates the self-seeding role that leads to few and multilayers MoSe 2. The presence of the defects in monolayer was confirmed by photoluminescence spectra analysis. The surface friction of the mono and few layers were studied experimentally using the lateral force microscopy. The surface friction of MoSe 2 depends on the number of layers presents in the surface flakes. Image 1 • MoSe 2 were prepared via a simple method and explain theoretically in the light MoO 3-x concentration. • Formation of nanoparticles at the center of the monolayer flakes due to temperature variations. • Surface friction measurements of the MoSe 2 using lateral force microscopy. [ABSTRACT FROM AUTHOR]

The energy stored in the crystallographic defects in nanocrystalline Ni-Mo alloy films was determined experimentally by differential scanning calorimetry (DSC) and compared with the calculated values. Two Ni-Mo layers with low (∼0.4 at.%) and high (∼5.3 at.%) Mo contents were processed by electrodeposition. It was revealed that the majority of the heat released during DSC (∼77%) was related to the grain boundaries. It was also found that the increase of Mo content from 0.4 to 5.3 at.% yielded an enhancement of the stored energy with a factor of about two. The measured and the calculated stored energies were compared with the values obtained for ultrafine-grained Ni-Mo alloys with similar compositions but processed by severe plastic deformation (SPD). It was revealed that in the SPD-processed samples there was a considerable contribution of vacancies to stored energy while their effect in the electrodeposited layers was lower. • The stored energy in Ni-Mo films was calculated and compared with calorimetry results. • About 77% of the stored energy was caused by grain boundaries. • Higher Mo content yielded larger stored energy with unchanged fraction of GB energy. • The specific GB energy in electroplated Ni-Mo alloys was estimated as 0.5–0.7 J/m2. • The electrodeposited films contained less vacancies than the SPD-processed samples. [ABSTRACT FROM AUTHOR]

Excellent high-temperature mechanical properties and high recrystallization temperature are crucial for molybdenum (Mo) alloys in practical applications. The microstructure and high-temperature mechanical properties of Mo-0.8%La 2 O 3 -2%ZrC alloys prepared by traditional powder metallurgy technology associated with cross rolling post treatment were investigated. Results showed that the Mo1950-rolled alloys had a fine grain size of about 1.65 μm due to hot cross rolling and high tensile strengths of 988 MPa and 189 MPa at room temperature and 1400 °C, respectively. SEM and TEM examinations indicated that although most of the large La 2 O 3 and ZrC particles were distributed along the grain boundaries, some nano-sized particles were well dispersed in intragranular zones. Particularly, dislocations were found to intercepted by the second phase particles in tensile samples, which could effectively enhance both the tensile strength and recrystallization temperature. Dislocation, grain refining, and second phase particles were all found to play important roles in strengthening the alloys below the recrystallization temperature, while second phase particle strengthening was the only strengthening mechanisms above the recrystallization temperature. Image 1 • Mo-La 2 O 3 -ZrC alloys were prepared by powder metallurgy and cross rolling process. • The density of the alloys was increased and the crystalline grains were refined. • Tensile strengths were 988 MPa and 124 MPa at room temperature and 1600 °C. • Three typical strengthening mechanisms play synergistical roles at room temperature. • Second phase particle strengthening was the only reinforcing mechanism above 1400 °C. [ABSTRACT FROM AUTHOR]

A method for synthesis of carbide containing composites by mechanical activation has been developed. A mixture of molybdenum oxide, carbon black and Al or Zn metal reductant have been treated for 15 min in air followed by a subsequent calcination in argon atmosphere at 800 °C. The elemental and phase composition, structure, texture and particle morphology of these composites were studied. Mechanically activated and calcined samples were found to contain 6.5 and 5.9% of the molybdenum carbide phase, respectively. • Carbide-containing composites were obtained by mechanical alloying in an air medium. • Technique for the removal of oxide impurities from the obtained composite was devised. • The composition and morphology of the carbide-containing composite were studied. [ABSTRACT FROM AUTHOR]

The kinetics analysis of homogenization in Inconel 718 superalloy needs much more attention. For instance, the activation energy of Laves phase dissolution has not been determined so far, which is required for characterization of the underlying mechanisms. In the present work, based on Johnson–Mehl–Avrami–Kolmogorov (JMAK) analysis, diffusion calculations, and experimental investigation of homogenization at different temperatures and holding durations, the kinetics of Laves phase dissolution was studied. The activation energy of 274.5 kJ/mol was determined in this respect, which is close to the activation energy for diffusion of Mo in Ni (288.15 kJ/mol). Moreover based on the diffusion coefficients, it was found that the diffusion of Mo in Ni is slower than those of Nb and Ti in Ni. These results were also supported by the calculations based on the diffusion distance and it was concluded that the back-diffusion of molybdenum in austenite is the controlling micro-mechanism for dissolution of the undesirable Laves phase in this common superalloy. Image 1 • Activation energy of 274.5 kJ/mol was determined for the dissolution of Laves phase. • Kinetic analysis was based on JMAK analysis, diffusion calculations, and experiment. • Back-diffusion of Mo is the controlling mechanism for Laves phase dissolution. [ABSTRACT FROM AUTHOR]

Searching for high-efficiency and earth-abundant electrocatalysts towards hydrogen evolution reaction (HER) is one of the most promising pathways to ameliorate environmental contamination. In this work, we report a facile protocol to achieve the synthesis of the coupled molybdenum carbide and molybdenum nitride (Mo 2 C/Mo 2 N), in which ammonium heptamolybdate (AHM) serves as molybdenum source and hexamethylenetetramine (HMT) is chosen as a N-containing carbon source. By virtue of adjusting the ratios of precursors and carbonization temperatures, a variety of products with different structural features and HER performance can be obtained. Compared to single component of carbide or nitride, the Mo 2 C/Mo 2 N hybrid prepared with AHM/HMT ratio of 1:2 at 700 °C shows superior catalytic activity, with an overpotential of 205 mV required to drive 10 mA cm−2 of current density and a Tafel slope of 71.8 mV dec−1. The boosted HER performance is attributed to the synergistic effect between Mo 2 C and Mo 2 N, and the electronic modulation of active sites due to N-doping. • Facile synthesis of coupled Mo 2 C/Mo 2 N hybrid is demonstrated. • The precursors composition and temperatures cause the change of phase structure. • The structure-performance correlation is investigated. • The heteroatom N doping could modulate the electronic structure of active sites. • The optimized catalyst presents favorable HER activity and excellent stability. [ABSTRACT FROM AUTHOR]

Abstract Li- and Mn-rich layered oxides can deliver high reversible capacity but suffer from severe voltage decay, which seriously impedes their commercial applications. However, high-nickel Li-rich layered oxides could normally present stable discharge voltage but tend to deliver low reversible capacity. In this work, high-nickel Li-rich layered oxides are doped by Mo via a facile sol-gel route to realize both high reversible capacity and minor voltage decay simultaneously. The superior performance could be ascribed to the reduced size of primary particles, the enhanced stability of lattice oxygen and more Mn4+/3+ redox couples effectively activated during the electrochemical reactions which are realized via Mo doping. The present study offers a new strategy to achieve high-performance high-nickel Li-rich layered oxides with both the stable discharge potential and high reversible capacity by modifying their morphologies, structures and chemistries via the introduction of proper alien elements which are believed to be the potential cathode candidates for next generation lithium-ion batteries. Highlights • Single phase Li 1.2 Ni 0.4 Mn 0.36 Mo 0.04 O 2 was synthesized via a facile sol-gel recipe. • Mo doping modifies the morphology and chemistry of high-nicke Li-rich Li 1.2 Ni 0.4 Mn 0.4 O 2. • Mo doping improves the rate capability of Li 1.2 Ni 0.4 Mn 0.4 O 2 significantly. • Mo doping increases capacity via oxygen loss reduction and more Mn4+/3+ redox couples activation. [ABSTRACT FROM AUTHOR]

Abstract Molybdenum oxides (MoO x) nanoparticles (NPs) have great optical and electronic features that make them suitable for potential applications such as surface enhanced Raman spectroscopy (SERS) and energy systems. However, there are very few papers that report the synthesis of MoO x NPs by using the laser ablation of solids in liquids (LASL) technique and they lack the explanation for the oxidation process. This work reports on the generation of NPs composed of molybdenum trioxide hydrated (MoO 3 · x H 2 O) (x = 1, 2) by using this method and its oxidation due to aging. A picosecond Nd:YAG laser was used and the per pulse laser fluence was varied from 5 to 20 J/cm2. Spherical NPs were obtained with average diameters from 48 to 141 nm, respectively. The absorption evolution of the obtained colloids was characterized by optical absorption spectroscopy, TEM was used to study the MoO x NPs morphology, size and structure and Raman spectroscopy to determine the material chemical composition. Highlights • Molybdenum oxide NPs were successfully synthesized by the LASL method. • Absorbance peaks of the MoO x NPs increased due to the aging process. • Absorbance peaks of the MoO x NPs shifted or broadened due to the aging process. • The NPs TEM images indicate that three types of MoO x NPs were formed. [ABSTRACT FROM AUTHOR]

Abstract In this novel research, the Direct Energy Deposition - Laser Additive Manufacturing (DED-LAM) process is used for deposition of β-type Titanium Molybdenum (Ti-15Mo) biomedical alloy. A major challenge in the successful deposition of an alloy powder on the substrate by the DED-LAM process is the formation of a strong metallurgical bond with minimum track dilution. Targeting a crack-free and dense multi-layer deposition, a detailed investigation of the effect of three key process parameters on the track geometry characteristics is conducted. The response surface methodology (RSM) experimental design technique and ANOVA based quadratic regression modeling are employed to relate the process parameters with track geometric characteristics. The statistical analysis results show that minimum track dilution is achieved at maximum laser power and minimum scan speed and powder feed rate. Further, microstructural characterization is carried out to analyse the porosity, elemental composition and phase constituents. Microhardness of 385 ± 8 HV and elastic modulus of 73 ± 1.5 GPa are achieved for the Ti-15Mo deposits at the optimum parameter settings. This study establishes a methodology towards successful deployment of the DED-LAM process for potential fabrication of Ti-15Mo alloy biomedical implants. Graphical abstract Image 1 Highlights • DED – LAM is successfully used for single-track deposition of β-type Ti-15Mo alloy. • Long columnar structures followed by epitaxial grain formation confirmed by SEM. • RSM optimization and ranking of 3 variables for minimum track dilution established. • High fidelity statistical models generated for four process responses. • Low porosity deposits with mechanical properties like wrought product obtained. [ABSTRACT FROM AUTHOR]

Abstract A fascinating strategy of molybdenum ions supporting was utilized to enhance green upconversion (UC) emissions of Er-Yb:TiO 2 prepared by sol-gel method. Er-Yb:TiO 2 nanoparticles exhibited irregular sizes approximately 100–350 nm, which showed stronger red emission and weaker green emissions under the irradiation of near-infrared (NIR). After molybdenum ions supporting, Er-Yb:TiO 2 nanoparticles were turned into uniformly dispersed eight prism structure and average particle size reached about 800 nm. Also, the green UC luminescence integrated intensity of Mo/Er-Yb:TiO 2 was about 46 times improved than that of Er-Yb:TiO 2. Furthermore, a novel photocatalyst of Mo/Er-Yb:TiO 2 @W 18 O 49 quasi-core/shell heterostructure was designed based on the localized surface plasmon resonances (LSPR) effect of W 18 O 49 through solvothermal process. With the excitation of NIR, the photocatalytic property of Mo/Er-Yb:TiO 2 @W 18 O 49 for H 2 producing from ammonia borane (BH 3 NH 3) was researched. H 2 production was about 2-fold enhancement compared with that of W 18 O 49. Besides, the application of natural sunlight for H 2 producing was provided. About 3 times H 2 yield was obtained in contrast to that of W 18 O 49. This work provided an effective way to enhance UC luminescence intensity and H 2 production efficiency for solving energy deficiency problems. Highlights • Er-Yb:TiO 2 showed regular eight prism structure after molybdenum ions supporting. • Mo/Er-Yb:TiO 2 showed 46-fold stronger green UC emissions than that of Er-Yb:TiO 2. • Using UC emissions to excite LSPR of W 18 O 49 for H 2 evolution from BH 3 NH 3. • Mo/Er-Yb:TiO 2 @W 18 O 49 showed 2-fold H 2 production than that of W 18 O 49. • 3-fold higher H 2 yield than that of W 18 O 49 was gained under focused sunlight. [ABSTRACT FROM AUTHOR]

Abstract A novel fast resistance sintering method has been developed to fabricate pure Mo bulk material with fine grain size and high sinter density. A pure Mo compact with more than 98.5% theoretical density and grain size less than 2 μm has been successfully fabricated without any sintering additive or grain growth inhibitor under ultra-high pressure of 9000 MPa, sintering temperature of 1300 °C for only 60 s. The relationships between microstructure, basic mechanical property and processing parameters, including pressure, input power and sintering time, were investigated. Highlights • Pure Mo with high density has been fabricated by a very fast resistance sintering method without any sintering aids. • The effects of pressure, sintering temperature and time on microstructure evolution were investigated. • The fabricated Mo shows fine grain microstructure without obvious grain growth. [ABSTRACT FROM AUTHOR]

Abstract This paper describes a systematic analysis of liquid-phase infiltrated molybdenum (Mo) copper (Cu) composites, deformed by various levels, and elucidates the impact of (i) the copper content, and (ii) the rolling reduction on the evolution of the material properties. The rolling-induced change of the thermo-physical properties can be traced back to (ii-a) the evolution of the geometry (viz. the flattening of the molybdenum and the copper phase during rolling) and (ii-b) the evolution of the crystallographic texture. Four infiltrated ingots with a copper content of 23, 39, 48 and 54 vol % were produced. Each ingot was gradually rolled down to a final degree of deformation of 0.5, 1, 1.5, 2 and 2.38, which corresponds to a rolling reduction of 39%, 63%, 78%, 86% and 90%. In summary, four material compositions (23, 39, 48 and 54 vol % Cu) in six conditions (as-infiltrated and five as-rolled conditions) were examined. The evolution of the microstructure is correlated with the evolution of the mechanical and thermo-physical properties such as hardness (HV2), Young's modulus, E , electrical conductivity, σ , thermal conductivity, k , and the coefficient of thermal expansion, α (CTE, in the range of 350 °C (623 K) – 750 °C (1023 K)). It was found, that the same thermal conductivity can be gained by using either a low copper-content composite that features a low degree of deformation or by using a high copper-content composite that was rolled down to a high degree of deformation. Furthermore, we were able to demonstrate that peculiarities in the CTE-over-T curves can be traced back to the plastic deformation of the copper phase, which is affected by rolling-induced residual stresses and recrystallisation processes during the CTE measurement. Graphical abstract Image 1 Highlights • Four liquid-phase infiltrated MoCu ingots were produced (Cu: 23, 39, 48, 54 vol %). • The ingots were rolled down to five degrees of deformation (0.5, 1, 1.5, 2 and 2.38). • Evolution of the thermal conductivity and expansion behaviour were analysed. • Material properties = f (copper content, degree of deformation (geometry, texture)). • The peculiar expansion behaviour is caused by the plastic deformation of the Cu phase. [ABSTRACT FROM AUTHOR]

Abstract Five Fe-30 wt%Mn-10.5 wt%Al-1.1 wt%C steels containing different Mo and Cr contents were prepared to investigate the effect of Mo and Cr addition on the microstructure, mechanical properties and pitting corrosion resistance of austenitic lightweight steels. The microstructures of all samples after solution treatment at 1050 °C consisted of austenite and κ-carbide, while DO 3 ordered phases were additionally formed in samples containing 3 wt%Mo-3wt%Cr or 5 wt%Cr. The results of Nanoindentation tests indicated that the intrinsic strength of the austenite matrix decreased with the addition of Mo and Cr due to the suppression of κ-carbide precipitation and then the strength of the DO 3 phase is equal or higher as compared to the austenite matrix. The tensile tests also showed that the yield strength decreased when 3 wt%Mo or 3 wt%Cr was added due to the suppression of κ-carbide precipitation, whereas it increased with further additions of Mo and Cr in both cases due to the formation of a DO 3 ordered phases and grain refinement. Electrochemical tests showed that the resistance to pitting corrosion was improved by the addition of Mo and Cr due to the formation of a protective passive film; however, the excessive additions of Mo or Cr adversely deteriorated the resistance to pitting corrosion as the DO 3 ordered phase which acted as pit initiation sites. Graphical abstract Image 1 Highlights • The addition of Mo and Cr suppressed the precipitation of κ-carbide within austenite. • DO 3 phase formed additionally in the samples containing 3 wt%Mo-3wt%Cr or 5 wt%Cr. • Tensile test results and nanohardness were correlated with precipitation behavior. • The formation of DO 3 phase deteriorated the resistance to pitting corrosion. [ABSTRACT FROM AUTHOR]

Abstract The classical molecular dynamics simulation was conducted to investigate the effect of Mo atom addition upon the atomic structure and glass-forming ability of Ni 64 Zr 36-x Mo x (x = 0, 6, 12, 18, 21, 24, 27) metallic glasses (MGs), in terms of the system energy, pair distribution functions (PDFs), and the largest standard cluster analysis. It is found that Mo atoms do not simply replace Zr atoms, but remarkably change the atomic and chemical order; resulting in a more stable, more compact and more complex structures indicated by the split of the first major peak on PDF curves. The addition of Mo atoms does not favor the formation of icosahedrons but enhances the topologically close-packed (TCP) structures that are not only responsible for the split of the first major peak on the PDF curves, but also positively correlation with the GFA predicted by formation enthalpy. Thus, as a superset of icosahedrons, TCP structures are one of the essential characteristic of MGs and significantly enhances the GFA of Ni 64 Zr 36-x Mo x ternary glass metals. These findings shed a new light on the understanding of the structure and the structure-GFA relationship of MGs. Graphical abstract Image 1 Highlights • The Mo-addition in Ni 64 Zr 36-x Mo x changes the s- and d-electronic structures. • Separated with x = 21 PDF curves, atomic volume, T g , and bond-length are different. • Bond length deduces or unchanges with x; Mo-Zr is abnormally the smallest one. • TCP rather than ICO is responsible for the split first peaks on PDF curves. • Amount evolution of TCP rather than ICO is consistent with GFA of alloys. [ABSTRACT FROM AUTHOR]

Abstract The high-temperature properties of the molybdenum sheet doped with 1.0 wt%Al 2 O 3 particles were investigated. The Al 2 O 3 particles have a good bond with the Mo matrix and there exists an amorphous transition layer at the interface between Al 2 O 3 particles and Mo matrix in the as-rolled sheet. The tensile strength of the Al 2 O 3 -doped Mo sheet is higher 23–62% than that of the pure Mo sheet at room and high temperatures, with its recrystallization temperature increased by about 200 °C than that of the pure Mo sheet. Furthermore, the fracture and strengthening mechanisms were discussed. Graphical abstract Image 1 Highlights • Preparation of the high-strength Molybdenum alloy sheet doped with nano-Al 2 O 3 particles by using the hydrothermal method. • The tensile strength at room and elevated temperatures were examined. • The microstructures (SEM and HRTEM) were investigated. • The fracture and strengthening mechanisms were discussed. [ABSTRACT FROM AUTHOR]

Abstract The present investigation deals with the fabrication of a novel thermally sprayed coating using a diamond reinforced molybdenum feedstock. Molybdenum powders were ball-milled with 10 wt% mono-crystalline diamond particles to produce a powder feedstock. Both milled and as-received powders were deposited on steel substrates using air plasma spraying to produce coatings with a thickness in the range of 250–280 μm. Characterisation of the coatings was performed in terms of micro-structure, phases, hardness, elastic modulus and residual stress. Retention of diamond in the composite coating was confirmed using Raman imaging. Micro-hardness and elastic modulus of coatings improved with diamond reinforcements. Graphical abstract Image 1 Highlights • Diamond-reinforced composite molybdenum coatings were prepared from ball-milled powder feedstock. • The micro-structure of the composite coatings contains both semi-molten and fully molten phases. • Diamond could be retained in the composite coatings. • Increase in hardness (∼10%) and elastic modulus (∼15%) was observed in composite coatings. [ABSTRACT FROM AUTHOR]

Abstract The paper considers the effect of sintering and copper infiltration processes on pseudoalloys nickel-molybdenum steel-copper structure and mechanical properties. The study is based on PZhR 3.200.28 and ASC 100.29 iron powders usage. Using iron powder ASC 100.29, that is less contaminated with related compounds, does not influence significantly the microstructure of copper-infiltrated steel. Pseudoalloys high mechanical properties are mainly associated with the large volume of deformation-induced austenite-to-martensite transformation in the zone of steel fracturing and martensite formation with nanoscale crystallites. The decrease in pseudoalloys austenite stability in comparison with powder steels is a result of a more homogenous distribution of alloying elements at sintering with present copper-based liquid phase. Highlights • Copper infiltration eliminates the erosion and fills the pores of steel samples. • The given distribution of alloying additions forms metastable austenite. • Deformation-induced austenite transformation increases properties of composites. • Homogenization equation predicts distribution of alloying additions authentically. [ABSTRACT FROM AUTHOR]

Abstract A ternary MoO 3 /TiO 2 /Ti 3 C 2 T x composite was successfully prepared through in-situ oxidation of Ti 3 C 2 T x and loading of MoO 3 nanoparticles by one-pot hydrothermal method. The obtained ternary composite was characterized by X-ray diffraction, XPS, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It could be clearly found that the TiO 2 nanoparticles and MoO 3 nanoparticles were well dispersed on the Ti 3 C 2 T x , larger TiO 2 nanoparticles were attached on the edges of Ti 3 C 2 T x layers and smaller MoO 3 nanoparticles were dispersed between Ti 3 C 2 T x layers. The nanoparticles extremely increase specific surface area of MoO 3 /TiO 2 /Ti 3 C 2 T x composite to 33.6 m2 g−1, and 9.8 m2 g−1 for as-prepared Ti 3 C 2 T x powder. Electrochemical properties testing results showed a specific capacitance of 162 F g−1 at a scan rate of 2 mV s−1 in the potential range from −1 V to −0.3 V with 1 mol L−1 KOH as electrolyte during the cyclic voltammetry (CV) cycles, which is superior to the performance of pure 2D layered Ti 3 C 2 T x. Also, the as-prepared ternary composites exhibited good specific capacitance retention of 91% after 8000 cycles. It is confirmed that the three components of ternary composites could make the integrated electrochemical behavior display and lead to a resulting capacitor with enhanced performance. The significant enhancement in electrochemical performance of the ternary composites can be attributed to the synergistic effect and cooperation of TiO 2 and MoO 3 nanoparticles dispersed on the Ti 3 C 2 T x sheets. Highlights • Tightly catching of TiO 2 nanoparticles and Ti 3 C 2 T x layers is important for electrical conductivity. • MoO 3 nanoparticles with high capacity also play an important role. • Ti 3 C 2 T x offers much active sites for electrochemical actions and nucleation-crystallization of TiO 2 and MoO 3 nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract In this study, the electrodeposition of the ternary Co-Mo-Re alloy from a complex citrate electrolyte has been investigated. The effect of solution pH, temperature and current density on the chemical composition, current efficiency and morphology of the obtained coatings is shown. It has been found that depending on the electrolysis parameters, four different types of surface morphology can be obtained. The high-quality bright adherent coatings can be obtained at two pH values. At pH 3.5, an alloy containing Со 35.5 -Мо 4.1 -Re 60.4 –Со 52.9 -Мо 10.8 -Re 36.3 аt.% deposits with a current efficiency of 20.3–84.5% at a current density of 20–60 mА сm−2, and at pH 6.3, an alloy containing Со 41.0 -Мо 29.5 -Re 29.5 deposits with a current efficiency of 47% at a current density of 20 mА сm−2. The optimal temperature for electrolysis is 50 °C. An increase in temperature as well as a decrease in temperature lead to the formation of spherulites. At a temperature of 70 °C, also with an increase in pH to 5.0, a powder of spherical shape with 20–30 μm particle size is formed. At pH over 6.5, fissured deposits are formed. Graphical abstract Image 1 Highlights • High-quality bright adherent coatings can be obtained at two pH values. • The optimal conditions for the deposition of alloy: pH 3.5, 500С, 20 mA cm-2. • Qualitative bright Co 41.0 -Mo 29.5 -Fe 29.5 at.% coatings can be obtained at pH 6.3. • The powder of spherical shape with 20-30 μm particle size can be obtained at pH 5. [ABSTRACT FROM AUTHOR]

A nanocrystalline metal's strength increases significantly as its grain size decreases, a phenomenon known as the Hall-Petch relation. Such relation, however, breaks down when the grains become too small. Experimental studies have circumvented this problem in a set of Ni-Mo alloys by stabilizing the grain boundaries (GB). Here, using atomistic simulations with a machine learning-based interatomic potential (ML-IAP), we demonstrate that the inverse Hall-Petch relation can be correctly reproduced due to a change in the dominant deformation mechanism as the grain becomes small in the Ni-Mo polycrystals. It is found that the atomic von Mises strain can be significantly reduced by either solute doping and/or annealing for small-grain-size polycrystals, leading to the increased strength of the polycrystals. On the other hand, for large-grain-size polycrystals, annealing weakens the material due to the large atomic movements in GB. Over a broad range of grain size, the superposition of the solute and annealing effects on polycrystals enhances the strength of those with small grain size more than those with large ones, giving rise to the continuous strengthening at extremely small grain sizes. Overall, this study not only demonstrates the reliability of the ML-IAP, but also provides a comprehensive atomistic view of complex strengthening mechanisms in nanocrystals, opening up a new avenue to tailor their mechanical properties. • Hall-Petch and inverse Hall-Petch relations can be correctly reproduced by machine learning interatomic potentials. • The atomic strain can be significantly reduced by either solute doping and/or annealing for small-grain-size polycrystals. • For large-grain-size polycrystals, annealing weakens the material due to the large atomic movements in GB. • The different effects on small- and large- grain alloys can lead to continuous strengthening down to extremely small sizes. [ABSTRACT FROM AUTHOR]

The development of efficient electrocatalysts using low-cost nanostructured transition metals as an alternative to noble metals is receiving strong interest in the field of clean and sustainable energy technology. In this study, highly dispersed bimetallic nickel-molybdenum nanoparticles on electrospun carbon nanofibers (Ni-Mo/CNFs) were prepared using a sol-gel-assisted electrospinning technique followed by calcination. The chemical composition of the Ni-Mo/CNFs with different ratios of Mo and their morphology have been characterized by various techniques. The SEM and TEM images revealed that the Ni 0.6 Mo 0.4 /CNFs had a nanofibrous morphology, the Ni-Mo nanoparticles were highly dispersed over carbon nanofibers, and the average particle size was 9.02 nm. The Mo ratio plays a crucial role in enhancing the electrochemical performance, and Ni 0.6 Mo 0.4 /CNFs showed higher electrocatalytic activity than other samples. The maximum current density of Ni 0.6 Mo 0.4 /CNFs was 10 and 43.89 mA/cm2 for the methanol oxidation at 0.45 and 0.75 V vs. Ag/AgCl, respectively, and the onset potential was 0.31 V. The synergistic effect between Ni and Mo NPs and the morphology and structure of substrate (CNFs) were responsible for its electrochemical performance. [Display omitted] • Bimetallic Ni/Mo supported on CNFs are fabricated by sol-gel-assisted electrospinning. • Ni-Mo/CNFs have a nanofibrous structure and bimetallic NPs are highly dispersed on CNFs. • The Mo content effect on the electrooxidation of methanol was investigated. • The co-catalyst of Mo shows good performance at 10% of its precursor weight is used. • Ni 0.6 Mo 0.4 /CNFs catalyst achieved a current density of 10 mA/cm2 at 0.45 V vs. Ag/AgCl. [ABSTRACT FROM AUTHOR]

In this study, LiLaMgW 1-x Mo x O 6 : Eu 3+ phosphors have been synthesized by high-temperature solid-state reaction method. By changing the W O charge transfer (CT) band through Mo 6+ substitution, the excitation band of obtained phosphors had been widened largely and could match well with the InGaN-based LED chips. The crystal structure, diffuse reflection spectra, photoluminescent properties of the LiLaMgW 1-x Mo x O 6 : 0.1Eu 3+ phosphors were investigated as a function of W/Mo ratio. The red shift of charge transfer band (CTB) was observed with the increase of Mo 6+ concentration. Density functional theory (DFT) were performed to calculate the band structure in order to support the excitation band modulation. Moreover, LiLa 1-y MgW 0.7 Mo 0.3 O 6 :yEu 3+ phosphors exhibit strong red emission. The excitation, emission spectra, decay dynamics and thermal stability of the phosphors had been measured and investigated in detail. The quenching concentration of Eu 3+ is up to 20 mol% and the concentration quenching is attributed to the dipole-dipole interaction. Finally, a white-LED device was fabricated by integrating a mixture of optimal red phosphor, commercial green- and blue-emitting phosphors with a near-ultraviolet (UV) InGaN-based LED chip. The results suggest that the Eu 3+ -activated LiLaMgW 0.7 Mo 0.3 O 6 phosphor is a promising red-emitting phosphor for white-LEDs. [ABSTRACT FROM AUTHOR]

Mo-doped nickel-rich LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) cathode material is prepared by a solid-state method to enhance the high voltage electrochemical performances of the NCM622 material for lithium-ion batteries. The molybdenum element is proved to be homogeneously distributed inside the particles of the NCM622 material according to the result from the EDS mapping of the particle cross-section. The effects of Mo doping on the crystal structure, morphology, electrochemical properties and high-temperature performances of the NCM622 material are investigated in detail. The Mo-doped sample delivers a discharge capacity of 203.1 mAh/g and a capacity retention of 82.96% after 100 cycles at 1C under a high cut-off voltage of 4.6 V. Besides, the Mo-modified material exhibits a better rate performance of 159.9 mAh/g at 8C and lower voltage fading compared with the unmodified material. The significant improvements in electrochemical properties are ascribed to the fact that trace Mo ions doped into the transition-metal layer help to enlarge the lithium slab spacing, stabilize the crystal structure and suppress the electrode polarization. It is also demonstrated that Mo doping effectively suppresses the pulverization of particles and reduces the charge transfer resistance according to the SEM and EIS analyses. [ABSTRACT FROM AUTHOR]

MoS 2 vertically standing nanosheets were prepared by metal-organic chemical vapor deposition using molybdenum hexacarbonyl (Mo(CO) 6 ) and 1,2-ethanedithiol (C 2 H 6 S 2 ) as precursors. The sulfur source was chosen as a less toxic alternative to the well-established hydrogen sulfide (H 2 S). These films were deposited between 500 and 800 °C resulting in different surface morphologies, from nanoparticles to vertically standing nanosheets. A highly (002) oriented 2H-MoS 2 film was obtained at 700 °C. The effect of the microstructure on the catalytic performance of hydrogen evolution reaction (HER) of the MoS 2 films was investigated. The Tafel slope varied from 68 to 94 mV/dec, showing that the microstructure of the films had an influence on their final electrochemical performance. Water contact angle analysis was used to study the surface wettability of the films, obtaining values from 60 to 121.2°. These results exhibited a quite consistent trend with the Tafel slope, indicating a significant effect of wettability and nanosheets edge exposure on the HER performance. [ABSTRACT FROM AUTHOR]

A suitable temperature range of Sm 2 Fe 17 alloy formed only was chosen to investigate the electroreduction of Sm 3+ on molybdenum and iron electrode in LiF-CaF 2 -SmF 3 molten salt, which were studied by CV and SWV at different temperatures and concentrations of Sm 3+ . The reduction of Sm 3+ to Sm 0 on the iron electrode included two steps. Firstly, a soluble-soluble reaction appears at −0.33 V vs. Cr/Cr 2 O 3 corresponds to the electroreduction of Sm 3+ to Sm 2+ . The electroreduction of Sm 3+ to Sm 2+ is a reversible process, which is controlled by the diffusion of Sm 3+ in the LiF-CaF 2 -SmF 3 molten salt. Secondly, Sm 2+ can be reduced at −0.78 V vs. Cr/Cr 2 O 3 on the iron electrode in LiF-CaF 2 -SmF 3 molten salt due to a lower activity of metallic samarium in the Sm 2 Fe 17 alloy than that of samarium metal, and that makes samarium in Sm-Fe alloy more stable while that of Sm 2+ could be not reduced by a molybdenum electrode. By experiment of potentiostatic electrolysis it was confirmed that the cathode product from LiF-CaF 2 -SmF 3 melts at −1 V vs. Cr/Cr 2 O 3 for 4 h is a thin layer metallic plate only composing Sm 2 Fe 17 alloy. [ABSTRACT FROM AUTHOR]

Endowing vanadium dioxide (VO 2 ) thin films with excellent thermal sensitive performance is greatly desired for application in uncooled infrared (IR) detectors. Here, we demonstrate a strategy of co-doping by using a simple and feasible CVD method to synthesize Mo-Al-doped VO 2 (B) thin films with high temperature-coefficient-of-resistance (TCR, −3.6%/K) and favorable square resistances (16.2 kΩ). Both the TCR and resistance are superior to that of undoped and Al-doped VO 2 (B) thin film, and the TCR is larger than that of Mo-doped VO 2 (B) thin film. The underlying microscopic mechanism for the performance improvement might be that Mo-Al co-doping creates less lattice deformation, strain and inhomogeneity of carrier concentration due to dimension and charge compensation than that of single-doping and the partly release of 3d electrons around V 4+ -V 4+ pairs in co-doping films. Besides, the special two-dimensional octahedral structure of monoclinic ( C 2/ m ) VO 2 (B) favors the strain control with doping. The films have been subjected to synchrotron radiation based X-ray photoelectron spectroscopy (SRPES) and X-ray absorption near edge structure (XANES) techniques to study the local atomic and electronic structure around V ions. The results indicated that the dopants of Mo and Al were incorporated into the VO 2 lattice and occupied some of the V lattice sites, resulting in the formation of the V 1-x-y Mo x Al y O 2 substitution solid solution. V L -edge and O K -edge XAS results identically verified that Mo-Al co-doping might create the least lattice deformation in films. Hence, the high performance of films proves that the co-doping strategy is suitable for uncooled infrared detector applications. [ABSTRACT FROM AUTHOR]