Mo Substitution Research Articles

Modulating the magnetic properties of MoS2 monolayers by group VIII doping and vacancy engineering.

In this work, density functional theory is adopted to study the electronic and magnetic properties of MoS2 monolayers combined with a single S vacancy defect and a group VIII (G8) atom dopant, in which the dopant is incorporated via Mo substitution. The calculated results show that the magnetic properties of monolayer MoS2 can be tuned by changing the distribution of the G8 atom and S vacancy. The S vacancy tends to decrease the net magnetic moment of the doped system when these two defects are in their closest configuration. By adjusting the distance between the dopant and the S vacancy, the doped MoS2 monolayer may show a variable net magnetic moment. In particular, all of the Ni-doped MoS2 monolayers show zero magnetic moment with or without an S vacancy. The mean-field approximation is used to estimate the Curie temperature (TC). Our results show that Fe, Co, Ru, Rh, Os and Ir-doped MoS2 monolayers are potential candidates for ferromagnetism above room temperature. The density of states calculations provide further explanations as to the magnetic behavior of these doped systems. These results provide a new route for the potential application of atomically thin dilute magnetic semiconductors in spintronic devices by employing monolayer MoS2.

Two-gap superconductivity inMo8Ga41and its evolution upon vanadium substitution

Zero-field and transverse-field muon spin rotation/relaxation ($\mu$SR) experiments were undertaken in order to elucidate microscopic properties of a strongly-coupled superconductor Mo$_{8}$Ga$_{41}$ with $T_{\text{c}}=9.8$ K. The upper critical field extracted from the transverse-field $\mu$SR data exhibits significant reduction with respect to the data from thermodynamic measurements indicating the coexistence of two independent length scales in the superconducting state. Accordingly, the temperature-dependent magnetic penetration depth of Mo$_{8}$Ga$_{41}$ is described using the model, in which two s-wave superconducting gaps are assumed. The V for Mo substitution in the parent compound leads to the complete suppression of one superconducting gap, and Mo$_{7}$VGa$_{41}$ is well described within the single s-wave gap scenario. The reduction in the superfluid density and the evolution of the low-temperature resistivity upon the V substitution indicate the emergence of a competing state in Mo$_{7}$VGa$_{41}$ that may be responsible for the closure of one of the superconducting gaps.

Synthesis and Characterization of V2-X Mo x O5 Cathode Materials for Calcium Ion Batteries

Recently, a great deal of attention has been paid to multivalent ion batteries as post lithium ion batteries (LIBs) [1]. Among them, calcium ion batteries (CIBs) could exhibit a high cell voltage and energy density due to the low standard electrode potential of Ca/Ca2+, -2.87 V vs. NHE, which is comparable to that of Li/Li+ (-3.05V vs. NHE). In addition, CIBs have attractive advantages such as the higher safety and lower cost compared with LIBs. However, there are only a few reports in which electrodes for CIBs show a reversible calcium ion insertion/extraction. Almost a decade ago, we found that some vanadium oxides, e.g. crystalline V2O5 with layer structure, undergo reversible reaction with Ca2+[2,3]. However, a V2O5 cathode exhibits the large overvoltage as well as the poor rate performances due to its low electronic conductivity. In this study, we studied the effect of substituting Mo6+ for a part of V5+ in V2O5 in order to improve the electronic conductivity of V2O5. The carrier electrons are expected to be generated by the substitution of Mo in terms of the so-called valence control expressed as V5+/V4+. We synthesized a series of Mo-substituted V2O5, i.e. V2-x Mo x O5 (x=0.02, 0.06, 0.1), by solid state reaction, and evaluated their electrochemical properties in comparison with a parent V2O5. XRD patterns of the synthesized V2-x Mo x O5 (x=0.02, 0.06, 0.1) powder all exhibited main diffraction peaks similar to those of V2O5 without impurity phases, indicating the solid solution formation. In addition, XPS measurements of V2p and Mo3d orbital showed main peaks attributed to V4+ and Mo6+ by Mo substitution in V2O5. Therefore, the V sites in V2O5 were suggested to be partially substituted to Mo. Galvanostatic cycling in LIBs revealed that a V1.94Mo0.06O5 electrode showed the lowest overvoltage than that of other compositions. Therefore, we focused on V1.94Mo0.06O5 in order to evaluate electrochemical characteristics for CIBs. The V1.94Mo0.06O5 cathode evaluated in CIBs showed reversible discharge and charge profiles with less overvoltage as well as the improvement in cycle performance compared to V2O5. XRD and EDX analyses also supported the reversible insertion/extraction reaction of V1.94Mo0.06O5 with Ca2+ ions. Therefore, it is suggested that V1.94Mo0.06O5is feasible as one of cathode materials for CIBs.

The effect of Mo doping on the structural and dielectric properties of Co-Zn ferrite

The effect of Mo doping on the structural and dielectric properties has been investigated in detail for Co-Zn spinel ferrite. Solid state reaction technique has been used to prepare the CZMO. The structural analysis is performed using HRXRD technique which confirms the inverse spinel structure of the material. The frequency and temperature dependence of dielectric constant are studied which reveals that the dielectric dispersion is due to Maxwell-Wagner type polarization in agreement with Koop's phenomenological theory. The contribution of grain and grain boundary at high and low frequency respectively are evident in the dielectric constant. The variation of dielectric loss tangent with both the temperature and frequency has been studied. The room temperature and high frequency dielectric loss is observed to be very small. Also it is revealed that the dielectric loss tangent decreases with Mo substitution.

Lattice dynamics and electronic structures of Ti3C2O2 and Mo2TiC2O2 (MXenes): The effect of Mo substitution

Recently, Mo2TiC2, an ordered two transition metals MXene has been synthesized, which offers a great opportunity to explore the effect of transition metal in MXenes. Here, the structure, dynamical and electronic properties of Mo2TiC2O2 and Ti3C2O2 are compared to investigate the effect of Mo substitution. Our density functional calculations predict that Mo2TiC2O2 prefer different structural configuration than the well-known Ti3C2O2. By comparing the dynamics and electronic structure between Mo2TiC2O2 and Ti3C2O2, we found that the replacement of Ti with Mo could enhance the chemical bonding and the electronic coupling of oxygen and carbon with metals. In addition, the GGA calculations show that Mo could change metallic Ti3C2O2 into semiconducting Mo2TiC2O2, which agrees with the recently experimental observation. Our calculations also show that spin-orbit coupling (SOC) effect is important to the electronic band structure of Mo2TiC2O2. The SOC could split the degenerate d bands on the Fermi level and the band inversion that is significant to the nontrivial band topology is found in Mo2TiC2O2. Our results indicate that Mo2TiC2O2 may be a two-dimensional topological (2D TI) semiconductor with band gap (HSE06+SOC) of 0.17eV.

Excellent rate performance and high capacity of Mo doped layered cathode material Li[Li0.2Mn0.54Ni0.13Co0.13]O2 derived from an improved coprecipitation approach

A Mo-doped layered cathode materials Li[Li0.2Mn0.54Ni0.13Co0.13]O2 (LMNC) with an excellent rate performance and high capacity have been successfully synthesized by a facile and novel organic co-precipitation process. The effect of trace Mo-doped on the surface morphology and crystal structures have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results reveal that the Mo6+-doped electrode material with an optimal content could show a uniform particles size distribution and well-crystallization. Electrochemical measurements, including charge-discharge, cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) have also been employed. It is demonstrated that the Mo-doped LMNC composites exhibit significant improvements on the electrochemical performance including the capacity, rate capability and cycle performance. For example, the initial discharge capacity is 260.8mAhg−1 at 1C for an optimal Mo-doped electrode, and still maintains an initial discharge capacity of 142.3 and 85.5mAhg−1 at 10 and 20C, and capacity retention could still be 83.56% and 96.14% after 100 cycles, respectively, indicating its excellent cycle and rate capability for LMNC materials. It is believed that the remarkably enhanced rate capability and cycling stability of these modified electrodes might be ascribed to trace Mo substitution prepared by this organic co-precipitation process.

Preparation of Ni-based bulk metallic glasses with high corrosion resistance

Bulk Ni77−x−yMoxCryNb3P14B6 (x=7 y=0; x=8 y=0; x=9 y=0; x=5 y=3; x=5 y=5; x=5 y=8; x=8 y=3; x=8 y=5, all in at.%) glassy alloy rods with the diameters of 1.0–1.5mm were synthesized by combining fluxing technique and J-quenching technique. The effects of Mo and Cr substitution for Ni on the glass forming ability (GFA), thermal stability, mechanical properties and corrosion properties of the present Ni-based bulk metallic glasses (BMGs) had been studied systematically. It is found that the substitution of an appropriate amount of Cr and Mo for Ni can enhance the GFA of the present Ni-based alloys, while excessive substitution will lead to the degradation of the GFA. The corrosion tests show that the corrosion current density and corrosion rate of most of the present Ni-based BMGs in 1M NaCl and 1M HCl solutions are in the order of 10−6A/cm2 and 10−2mm/year, respectively, exhibiting very high corrosion resistance. The addition of the appropriate Mo content and the Cr content as much as possible are benefit for the enhancement of the corrosion resistance of the present Ni-based BMGs. The compressive tests show that that the present Ni-based BMGs exhibit a compressive strength of 2.5–3.4GPa, but nearly zero compressive plasticity.

Improvement in rate capability of lithium-rich cathode material Li[Li0.2Ni0.13Co0.13Mn0.54]O2 by Mo substitution

Lithium-rich cathode material Li[Li0.2Ni0.13Co0.13Mn0.54]O2 doped with trace Mo is successfully synthesized by a sol-gel method. The X-ray diffraction patterns show that trace Mo substitution increases the inter-layer space of the material, of which is benefiting to lithium ion insertion/extraction among the electrode materials. The (CV) tests demonstrate the decrease of polarization, and on the other hand, the lithium ion diffusion coefficient (DLi) of the modified material turns out to be larger, which indicates a faster electrochemical process. As a result, the Mo doped material possesses high rate performance and good cycling stability, and the initial discharge capacity reaches 149.3 mAh g−1 at a current density of 5.0 °C, and the residual capacity is 144.0 mAh g−1 after 50 cycles with capacity retention of 96.5 % in the potential range of 2.0–4.8 V at room temperature.

Structural, Magnetic, and Optical Performance of Al and Mo Doped GaFeO3

Al-and Mo-doped GaFeO3 (Ga1−x Al x FeO3, GaFe1−x Mo x O3) multiferroic systems were fabricated by double-sintering ceramic method. Single phase of orthorhombic structure with space group Pc21n has been obtained. The structure parameters, bond length, and preferential cation distribution were derived from analyzing XRD applying Rietveld method. Rietveld refinement reveals the decrease and increase of the lattice parameters upon Al and Mo doping, respectively. The magnetic properties were studied thoroughly both doped systems. Curie temperatures (T C) change with increasing Al content amount and reach their maximum value for Al-substituted amounts 15 and 25 % (228 K). On other hand, as the amount of Mo increases, T c for GaFeO3, (GFO) decreases. Photoluminescence (PL) spectroscopic measurements were carried out at room temperature, under 330 nm excitation, to sense the reflection of Al and Mo substitutions on the investigated GFO lattice. The presence of the site disorder and cation redistribution was confirmed by PL emission spectral analysis. Fe 3+ ions at the tetrahedral and octahedral sites show entirely different luminescence. It was also inferred from the spectra that, at lower Mo content (x), the dominated higher intense PL emissions come from tetrahedrally coordinated Ga3+ ions, while in Al-doped GFO at higher Al content (x), the emissions come mainly from the octahedrally sited ions. The luminescent emissions will open up the opportunity of GFO-doped transition metals for both further fundamental studies and technological applications.

Magnetotransport properties of Mo substituted La0.7Ca0.3Mn1−xMoxO3 perovskites

We studied the effects of Mo substitution on the structural, transport, and magnetic properties of the La0.7Ca0.3Mn1−xMoxO3 (x ≤ 0.1) samples. Powder X-ray diffraction analysis reveals that the samples studied crystallize in the orthorhombic structure with space group Pbnm. Both particle size and morphology change significantly as the Mo content x varies. The metal-insulator transition temperature (TMI) and Curie temperature (TC) decrease monotonically as x increases. Magnetization data reveal that long-range FM ordering persists in all samples and the saturation moment decreases linearly as x increases. The smaller depression rate of dTC/dx observed is mainly ascribed to the increased amount of Mn2+ ions with Mo doping, which opens the FM coupling between Mn2+–O–Mn3+ in the samples.

Effects of Mo substitution for Ni on the microstructure and property of V-based hydrogen storage alloys

In order to study the property the V-based hydrogen storage alloys, Ni in the alloys was partially substituted by Mo. The V 2 Ti 0.5 Cr 0.5 Ni 1-x Mo x (x=0.02-0.08) hydrogen storage alloys were prepared by induction melting, and the effects of Mo content on the microstructure and electrochemical property were investigated systematically. The results show that the alloys mainly consist of a V-based solid solution phase with a BCC structure and a TiNi-based secondary phase. The electrochemical measurements indicate that with increasing the content of Mo, the maximum discharge capacity, the cycle stability and high rate discharge ability is increased first and then decreased.

Effect of Mo substitution on structural and magnetic properties of Zinc ferrite nanoparticles

Nano ferrite ZnFe2-xMoxO4 (x = 0.0, 0.1, 0.2, and 0.3) samples were synthesized by using citrate method. The phase purity and the structure parameters were studied using X-ray diffraction, FT-IR spectroscopy, and magnetic measurements. Rietveld analysis of X-ray diffraction data revealed that Mo doping ZnFe2O4 changes the degree of inversion of Zn2+ cations. The oxidation state of Mo was studied by using FTIR analysis. Mo doped ZnFe2O4 has a ferromagnetic properties. The magnetization decreases by the replacement of Fe3+ ions by non-magnetic Mo3+ ions. Mo doped ZnFe2O4 samples have a very small coercive field (Hc), which changes depending on the amount of Mo in the sample and reach its maximum value for ZnFe1.7Mo0.3O4. Cation distribution is proposed in an attempt to explain the experimental results of XRD, IR, and VSM data. The direct proportion between the coercive field and the Fe2+ content in the samples was studied in detailed.

Thermoelectric properties of Cr1−xMoxSi2

The thermoelectric properties of Mo-substituted CrSi2 were studied. Dense polycrystalline samples of Mo-substituted hexagonal C40 phase Cr1−xMoxSi2 (x=0–0.30) were fabricated by arc melting followed by spark plasma sintering. Mo substitution substantially increases the carrier concentration. The lattice thermal conductivity of CrSi2 at room temperature was reduced from 9.0 to 4.5Wm−1K−1 by Mo substitution due to enhanced phonon–impurity scattering. The thermoelectric figure of merit, ZT, increases with increasing Mo content because of the reduced lattice thermal conductivity. The maximum ZT value obtained in the present study was 0.23 at 800K, which was observed for the sample with x=0.30. This value is significantly greater than that of undoped CrSi2 (ZT=0.13).

Improved Electron/Li-Ion Transport and Oxygen Stability of Mo-Doped Li2MnO3

Li2MnO3 plays significant roles in stabilizing the structure and ensuring a high specific lithium storage capacity of the Li-rich layered xLi2MnO3·(1-x)LiMO2 (M = Ni, Co, Mn, etc.) composites (or solid solutions) as cathode materials for lithium ion batteries (LIBs)1. Nevertheless, it meets challenges in irreversible structural transition and low coulombic efficiency due to the loss of oxygen in the initial charge process. In addition, its insulating property deteriorates the rate performance of the xLi2MnO3·(1-x)LiMO2. These drawbacks hinder the commercialization and application of the composites as cathode materials for LIBs. Elemental substitution or atom doping has been commonly applied to improve the electrochemical performances of Li2MnO3 2-4. In an electrochemical viewpoint, as Mn4+ cannot be further oxidized in octahedral coordination in the pristine Li2MnO3, the charge compensation has to be conducted by the oxidation of the O2- ions alone upon Li-ion extraction, leading to irreversible structural change and safety issues. In contrast, as Mo4+ is potentially oxidized to Mo6+, the charge compensation will be largely declined from oxygen if multi-electron transfer occurs on the doped transition metal atoms in Li2Mn1-x Mo x O3. Therefore, substituting Mn with Mo is expected to reduce the loss of oxygen and improve the stability of the structure. In addition, considering the difference of Li2MnO3 (red) and its iso-structured Li2MoO3 (black) in color, Mo substitution for Mn might also improve the conductivity and rate performance of Li2MnO3and its related cathode materials. In this work, first-principles calculations are conducted to predict the impacts of molybdenum (Mo) doping on the physical and electrochemical properties of Li2MnO3. It demonstrates that Mo doping is indeed beneficial in improving both the dynamic and thermodynamic properties of Li2MnO3: (1) It decreases the band gap and increases the number of states around the Fermi level; (2) It enhances Li-ion diffusion especially between the lithium layer and the transition-metal layer; (3) Extra charge is transferred from Mo to O, accompanied with the reduction of the delithiation potential; (4) The charge of the removed Li-ion is compensated by both Mo and O in the Mo-doped Li2MnO3 during delithiation, and (5) Mo doping delays oxygen release and reinforces the stability of the structural oxygen based on the calculated reaction enthalpy. Therefore, Mo doping is expected to be an effective way in improving the structural stability and rate performance of Li2MnO3 and xLi2MnO3·(1-x)LiMO2 cathode materials. These findings will facilitate the investigation and promote the development of Li2MnO3 and xLi2MnO3·(1-x)LiMO2 cathode materials. M. M. Thackeray, S.-H. Kang, C. S. Johnson, J. T. Vaughey, R. Benedek and S. A. Hackney, J. Mater. Chem., 17, 3112-3125 (2007).M. Tabuchi, Y. Nabeshima, K. Ado, M. Shikano, H. Kageyama and K. Tatsumi, J. Power Sources, 174, 554-559 (2007).D. Mori, H. Sakaebe, M. Shikano, H. Kojitani, K. Tatsumi and Y. Inaguma, J. Power Sources, 196, 6934-6938 (2011).S. Kim, J.-K. Noh, S. Yu, W. Chang, K. Y. Chung and B.-W. Cho, J. Electroceram., 30, 159-165 (2013).

Magnetic hardening of CeFe12−xMox and the effect of nitrogenation

Abstract We report the magnetic hardening of CeFe 12− x Mo x by melt spinning at surface wheel speeds between 10 m/s and 30 m/s. The synthesis range of CeFe 12− x Mo x has been extended to CeFe 11 Mo, which uses the least amount of Mo substitution to stabilize the ThMn 12 -type structure. X-ray diffraction indicates that as-spun samples are multi-phased, typically consisting of a primary ThMn 12 -type phase with impurity phases of Fe–Mo alloy, Ce 2 Fe 17 and CeFe 2 . However, nearly pure ThMn 12 -type phase can be obtained either by directly melt spinning at specific wheel speeds or by annealing the over-quenched ribbons at an optimum temperature. The magnetic moment of CeFe 12− x Mo x is found to be affected not only by the number of Fe atoms but also by weakening of the Fe moment from Mo substitution. Nitriding is effective in enhancing the Curie temperature T c and saturation magnetization 4π M s . T c was enhanced by at least 151 °C after nitrogenation for all compositions. The newly identified CeFe 11 Mo compound exhibits the best magnetic properties in the alloy series, having T c = 370 °C and 4π M s > 13.0 kG after nitriding and ( BH ) max = 0.3 MGOe after annealing.

Physical Properties of Mo-Doped Cu(Re0.69−x Mo x Ca0.31)Sr2O6, x=0.1 to 0.6 Cuprate Perovskites

The physical properties of high-pressure synthesized polycrystalline Cu(Re0.69−x Mo x Ca0.31)Sr2O6 samples are reported in this article to attract the scientific community. The present system undergoes a structural phase transition from cubic symmetry (for x=0, 0.1) to tetragonal for 0.2≤x≤0.4 and again cubic perovskite structure for x=0.5 and 0.6. The pristine compound (x=0) undergoes a ferromagnetic (ferrimagnetic) transition with high T c∼460 K. Neither the Curie temperature nor the effective magnetic moment is enhanced upon Mo substitution. The mechanism of the suppression of ferromagnetism in the present system is discussed assuming a localized electron system which is reminiscent of W substitution (Balamurugan et al. in J. Appl. Phys. 101:09N501, 2007). The temperature dependence of electrical resistivity, ρ decreases with x=0–0.4 and then increases for x=0.5 and 0.6. Though the suppression of ferromagnetism in the present system is similar to W-substitution, interestingly the former one (Mo) shows different results on structural and transport electrical properties which urge for further studies. The interesting aspect of the present work is for x=0.6, the specific heat data shows significant electronic contribution, whereas the resistivity measurement reveals insulating behavior.

The effect of thermal stability for high-Ni-content layer-structured cathode materials, LiNi0.8Mn0.1−xCo0.1MoxO2 (x = 0, 0.02, 0.04)

Improving thermal stability is one of the most serious issues concerning Ni-based cathode materials for Li ion batteries. To increase the capacity for maintaining good thermal stability, we substitute Mo for Mn. We apply differential scanning calorimetry (DSC), thermal desorption spectrometry-mass spectrometry (TDS-MS), and X-ray diffraction (XRD) to elucidate the effect of Mo substitution. The application of DSC indicates that Mo substitution effectively reduces the exothermic reaction between the cathode and electrolyte. The applications of TDS-MS and XRD indicate that Mo substitution suppresses crystal structure change and reduces the oxygen release that accompanies heating below 350 °C. However, the discharge capacities of Mo-substituted samples are lower than that of sample without Mo substitution. We optimize the Li/transition metal ratio and obtain Li1.10Ni0.8Mn0.06Co0.1Mo0.04O2+δ, which satisfy both high capacity and high thermal stability requirements.

Spin glass to superconducting phase transformation by oxidation of a molybdo-cuprate: Mo0.3Cu0.7Sr2TmCu2Oy

A detailed study of the structure and properties for the as-prepared and oxygen annealed Mo0.3Cu0.7Sr2TmCu2Oy material is reported. The Cu/Mo cationic distribution is established using a combination of x-ray/neutron powder diffraction refinement. The chemical substitution of the Mo ions for the Cu ions in the CuYSr2Cu2O7−δ structure is found to occur in both of the copper sites for the as-prepared sample. Interestingly, no trace of Mo substitution in the copper plane site is found to occur after oxygenation. The as-prepared Mo0.3Cu0.7Sr2TmCu2Oy material is found to be a spin glass (SG) system and explained on the basis of the cluster-by-cluster freezing model. On the other hand, the oxygen annealed material is superconducting (SC) (TSC,onset = 31 K). A peak has been observed in the critical current density plot and can be explained on the basis of field induced pins. The influence of oxygen annealing in the structure and properties of this material are presented and discussed. This seems to be the first case of a SG–SC transformation following an oxidation reaction in cuprates.

Relationship between Ferroelectric Performance, Crystal and Electronic Structures in SrBi2(Ta1-xNbx)1.95M0.05O9 (M = W, Mo)

SrBi2(Ta1-xNbx)1.95M0.05O9 (x = 0∼1; M = W and Mo) were investigated from the viewpoint of ferroelectric properties, crystal and electronic structures. By P-E hysteresis-loop and dielectric-constant measurements, it was demonstrated that both the W- and Mo-substituted samples exhibited higher remanent polarization and lower Curie temperature regardless of the Ta:Nb ratio. The Rietveld technique with the neutron diffraction data indicated that the tilting angles of the (Ta,Nb,M)-O6 octahedra and the spontaneous polarization increased by the W and Mo substitutions. Such a change in the crystal structure explained well the behavior of the ferroelectric property. From electron-density analysis using synchrotron X-ray diffraction patters, it was suggested that the bond strength within the (Ta,Nb,M)-O6 octahetron became weaker slightly by the partial replacements of W and Mo.

Effect of Al and Mo substitution on the structural and hydrogen storage properties of CaNi5

A simple mechanical milling and annealing process has been used to synthesize CaNi5-based hydrogen storage alloys. Heat treatment at 800 °C under vacuum results in the formation of a crystalline CaNi5 phase. Secondary phases, including Ca2Ni7 and Mo–Ni, are formed when substituting Mo for Ni. Replacement of Ni by Al or Mo leads to an increase in the unit cell volume of the CaNi5 phase. The hydrogen storage capacity of all substituted alloys is reduced and the plateau pressures are lower than those of pure CaNi5. Fairly flat plateau regions are retained for all compositions except the CaNi4.8Mo0.2 composition where a Ca2Ni7 phase is dominant. The incorporation of Mo also causes slow sorption kinetics for the CaNi4.9Mo0.1 alloy. CaNi4.9Al0.1 maintains its initial hydrogen absorption capacity for 20 cycles performed at 85 °C but the other substituted alloys lose their capacity rapidly, especially the CaNi4.8Mo0.2 composition.