Hydride Nanoparticles Research Articles

Size-dependent phase change in energy storage materials: Comparing the impact of solid-state wetting and of coherency stress.

Coherent phase transformations in interstitial solid solutions or intercalation compounds with a miscibility gap are of practical relevance for energy storage materials and specifically for metal hydride or lithium-ion compound nanoparticles. Different conclusions on the size-dependence of the transformation conditions are reached by modeling or theory focusing on the impact of either one (internal, solid-state-) critical-point wetting of the nanoparticle surface or coherency constraints from solute-saturated surface layers. We report a hybrid numerical approach, combining atomistic grand canonical Monte Carlo simulation with a continuum mechanics analysis of coherency stress and modeling simultaneously wetting and mechanical constraints. When the ratio between chemical and misfit-strain-related contributions to the solute-solute interaction energy takes values realistic for interstitial solutions-which are typical for energy storage materials-we find that the impact of solid-state wetting is weak and that of coherency stress is dominant. Specifically, mechanical interaction can act to reduce the phase transformation hysteresis at small system size, and it can make the solid more binding for solute, thereby reducing the "plateau" chemical potential at phase coexistence. We present equations for the impact of coherency stress on the size-dependence of upper consolute temperature, plateau chemical potential, and charging/discharging hysteresis.

Direct Imaging of Electrochemical Palladium Hydride Formation from PdCoO2 for Highly Efficient Hydrogen Evolution Reaction

Active and reliable electrocatalysts are fundamental to renewable energy technologies.[1] PdCoO2 has recently been recognized as a promising catalyst for the hydrogen evolution reaction (HER) in acidic media.[2] This study unveils the activation mechanism of PdCoO2, highlighting two key processes: the leaching of Co atoms from the structure and the formation of palladium hydride (PdHx) nanoparticles.The former process is studied by operando measurement of Co dissolution and found to be kinetically related to the HER. Scanning electron microscopy cross-sections of PdCoO2 after prolonged HER reveal a thorough transformation towards the PdHx phase. The as-formed hydride nanoparticles were found to be stable up to anodic potentials of 0.8 V (with respect to reversible hydrogen electrode at pH = 1).The latter, i.e. the formation of hydrides, is confirmed through secondary ion mass spectrometry and quantitatively analyzed by atom probe tomography. By employing deuterium as a proxy for hydrogen, we identified the PdDx phase and determined a D/Pd atomic ratio of 0.28.Our findings highlight the critical role of palladium hydride formation in understanding the high performance of the HER catalyst derived from PdCoO2, offering insights into the design of more efficient electrocatalysts for renewable energy technologies.

Covalent Carbide Interconnects Enable Robust Interfaces and Thin SEI for Graphite Anode Stability under Extreme Fast Charging.

Carbonaceous and carbon-coated electrodes are ubiquitous in electrochemical energy storage and conversion technologies due to their electrochemical stability, lightweight nature, and relatively low cost. However, traditional reliance on conductive additives and binders leads to impermanent electrical pathways. Here, a general approach is presented to fabricate robust electrodes with a progressive failure mechanism by introducing carbide-based interconnects grown via carbothermal conversion of (5 wt%) titanium hydride nanoparticles. This method concurrently enhances both electrical and mechanical properties within the electrode architecture. The resulting chemical bonding between active materials establishes a novel mechanism to maintain stable electrical pathways during cycling. Employed as Li-ion battery anodes, these electrodes exhibit improved cyclability, achieving 80% capacity retention after 800 fast-charge cycles at moderate loading (1 mAh cm- 2). High loading cells with areal capacity of 3 mAh cm-2 show significantly improved cycle lifeover the same number of cycles. This performance improvement is attributed to the absence of significant impedance growth and a thinner solid electrolyte interphase (SEI) layer formed at high current densities (4C) as demonstrated by X-ray photoelectron spectroscopy and transmission electron microscopy studies. The enhanced conductivity facilitates SEI formation, lowering ionic impedance and mitigating lithium plating, ultimately leading to the reported extended cycle life.

Expression of Concern: Molecular dynamics simulation of combustion behavior of coated aluminum hydride nanoparticles in the oxygenated medium: Effects of adding the ethanol atomic coating

Expression of Concern: Molecular dynamics simulation of combustion behavior of coated aluminum hydride nanoparticles in the oxygenated medium: Effects of adding the ethanol atomic coating

Mxene-supported NbVH nanoparticles as efficient catalysts for reversible hydrogen storage in magnesium borohydride

Bimetallic niobium vanadium hydride nanoparticles (NbVH NPs) anchored on Ti3C2 were synthesized using a facile ball milling method as an effective catalyst for the dehydrogenation kinetics and reversibility of Mg(BH4)2. It was found that the onset dehydrogenation temperature of the Mg(BH4)2 + 30NbVH NPs@Ti3C2 composite was 105.7 °C and released 9.07 wt% of hydrogen at 330 °C, while undoped Mg(BH4)2 only released 4.2 wt% of H2 from 248 °C to 330 °C. Additionally, the Mg(BH4)2 + 30NbVH NPs@Ti3C2 composite achieved remarkable hydrogen release of over 9.44 wt% at a temperature as low as 230 °C, indicating unexpected dehydrogenation kinetics. In the reversible hydrogen desorption tests, Mg(BH4)2 + 30NbVH NPs@Ti3C2 released 5.98 wt% of H2 in the 2nd cycle at 250 °C and maintained a reversible capacity of 4.35 wt% after 10 cycles, demonstrating a remarkable enhancement in reversibility. The enhancement in the dehydrogenation kinetics of Mg(BH4)2 could be attributed to the greatly reduced activation energies from 343 kJ·mol−1 and 138.3 kJ·mol−1 to 103.7 kJ·mol−1 and 124 kJ·mol−1. Investigations on the evaluation of catalyst and Mg(BH4)2 during reversible hydrogen storage have revealed that NbVH NPs actually acted as a “bidirectional hydrogen pump”, facilitating both the hydrogen release and uptake from Mg(BH4)2. This strategy of multi-component hydrides may show a new way to design effective catalysts for solid-state hydrogen storage materials.

Expression of Concern: The effect of penetrated oxygen particles on combustion time of coated Al hydride nanoparticles in an oxygenated medium by applying molecular dynamics method via Lennard-Jones and reactive force-field potentials

Expression of Concern: The effect of penetrated oxygen particles on combustion time of coated Al hydride nanoparticles in an oxygenated medium by applying molecular dynamics method via Lennard-Jones and reactive force-field potentials

Microfluidic Synthesis of CuH Nanoparticles for Antitumor Therapy through Hydrogen-Enhanced Apoptosis and Cuproptosis.

Cuproptosis has drawn enormous attention in antitumor material fields; however, the responsive activation of cuproptosis against tumors using nanomaterials with high atom utilization is still challenging. Herein, a copper-based nanoplatform consisting of acid-degradable copper hydride (CuH) nanoparticles was developed via a microfluidic synthesis. After coating with tumor-targeting hyaluronic acid (HA), the nanoplatform denoted as HA-CuH-PVP (HCP) shows conspicuous damage toward tumor cells by generating Cu+ and hydrogen (H2) simultaneously. Cu+ can induce apoptosis by relying on Fenton-like reactions and lead to cuproptosis by causing mitochondrial protein aggregation. Besides, the existence of H2 can enhance both cell death types by causing mitochondrial dysfunction and intracellular redox homeostatic disorders. In vivo experimental results further exhibit the desirable potential of HCP for killing tumor cells and inhibiting lung metastases, which will broaden the horizons of designing copper-based materials triggering apoptosis and cuproptosis for better antitumor efficacy.

Revealing the Hidden Role of Radical Scavengers: Unraveling the Key to Tailoring the Formation of the hcp PdHx Phase in Graphene Liquid Cells

AbstractRadiation chemistry enables the synthesis of colloidal nanoparticles without chemical reducing agents, yielding metal nanoparticles via simple and direct processes. Aliphatic alcohols are widely used to promote the formation of nanoparticles in radiolytic synthesis by inhibiting the reoxidation of these metal nanoparticles by scavenging hydroxyl radicals. However, the role of the scavenger has been limited to simply accelerating the formation of the nanoparticles without altering their nature. Herein, the role of radical scavengers is investigated in determining the type of metal nanoparticles formed, with the scavenger concentration playing a crucial role. It is found that the addition of isopropyl alcohol controls the formation of hexagonal close‐packed (hcp) palladium hydride (PdHx) nanoparticles that are previously synthesized for the first time via radiation chemistry by increasing the concentrations of hydrated electrons and hydrogen radicals. This discovery reveals a more active role for radical scavengers in radiolytic syntheses, and this strategy can be used for the cost‐effective mass production of hcp PdHx nanoparticles.

The effect of initial conditions (temperature and pressure) on combustion of Fe-coated-aluminum hydride nanoparticles using the molecular dynamics approach

Highly combustible elements like beryllium, lithium, Al, Mg, and Zn have the highest combustion, increasing the heat in explosives and propellants. Al can be used because of its greater availability. Reducing the size of Al nanoparticle (NP) increases the combustion rate and decreases the combustion time. This paper studied the effect of initial conditions on the phase transition (PT) and atomic stability times of Fe-coated-aluminium hydride (AlH3) NPs. The molecular dynamics (MD) technique was used in this research. The microscopic behavior of structures was studied by density (Den.), velocity (Vel.), and temperature (Tem.) profiles. Heat flux (HF), PT, and the atomic stability of the structure were examined at different initial pressures (IP) and initial temperatures (IT). According to the achieved results, Den., Vel., and Tem. values had a maximum value of 0.025 atoms/Å3, 0.026 Å/ps, and 603 K. By increasing IT in the simulation box to 350 K, HF in the samples increases to 75.31 W/m2. Moreover, the PT time and atomic stability time by increasing IP reach to 5.93 ns and 8.96 ns, respectively. Regarding the importance of the phenomenon of heat transfer and PT of nanofluids (NFs), the findings of this study are predicted to be useful in various industries, including medicine, agriculture, and others.

Enhancing the Combustion of Magnesium Nanoparticles via Low-Temperature Plasma-Induced Hydrogenation.

The hydrogenation of metal nanoparticles provides a pathway toward tuning their combustion characteristics. Metal hydrides have been employed as solid-fuel additives for rocket propellants, pyrotechnics, and explosives. Gas generation during combustion is beneficial to prevent aggregation and sintering of particles, enabling a more complete fuel utilization. Here, we discuss a novel approach for the synthesis of magnesium hydride nanoparticles based on a two-step aerosol process. Mg particles are first nucleated and grown via thermal evaporation, followed immediately by in-flight exposure to a hydrogen-rich low-temperature plasma. During the second step, atomic hydrogen generated by the plasma rapidly diffuses into the Mg lattice, forming particles with a significant fraction of MgH2. We find that hydrogenated Mg nanoparticles have an ignition temperature that is reduced by ∼200 °C when combusted with potassium perchlorate as an oxidizer, compared to the non-hydrogenated Mg material. This is due to the release of hydrogen from the fuel, jumpstarting its combustion. In addition, characterization of the plasma processes suggests that a careful balance between the dissociation of molecular hydrogen and heating of the nanoparticles must be achieved to avoid hydrogen desorption during production and achieve a significant degree of hydrogenation.

Palladium-based multifunctional nanoparticles for combined chemodynamic/photothermal and calcium overload therapy of tumors.

Due to the high mortality and incidence rates associated with tumors and the specificity of the tumor microenvironment (TME), it is difficult to achieve a complete cure for tumors using a single therapy. In this study, calcium carbonate-modified palladium hydride nanoparticles (PdH@CaCO3) were prepared and utilized for the combined treatment of tumors through chemodynamic therapy (CDT)/photothermal therapy (PTT) and calcium overload therapy. After entering tumor cells, PdH@CaCO3 releases calcium ions (Ca2+) and PdH once it reaches the TME due to the pH reactivity of the calcium carbonate coating. The mitochondrial membrane potential is lowered by the Ca2+, leading to irreversible cell damage. Meanwhile, PdH reacts with excessive hydrogen peroxide (H2O2) in the TME via the Fenton reaction, generating hydroxyl radicals (·OH). Moreover, PdH is an excellent photothermal agent that can kill tumor cells under laser irradiation, leading to significant anti-tumor effects. In vitro and in vivo studies have demonstrated that PdH@CaCO3 could combine CDT/PTT and calcium overload therapy, exhibiting great clinical potential in the treatment of tumors.

Influences of adding Y2Ti2O7 and HfH1.98 nanoparticles on the microstructure and mechanical properties of oxide dispersion strengthen steels

Adding Y2O3 will make Al-containing oxide dispersion strengthened (ODS) steels produce coarse Y-Al-O particles, which deteriorates their mechanical properties. Herein, Y2Ti2O7 nanoparticles and Hf hydride nanoparticles (NPs) were successfully prepared by hydrogen plasma-metal reaction (HPMR) method and added together in the Fe-Cr-Al ODS steel to replace the traditional Y2O3 NPs. The microstructure of matrix and oxide in ODS steels has been characterized by scanning transmission electron microscopy (STEM) and high resolution transmission electron microscopy (HRTEM). The oxide NPs in FHYT-0.6 (Fe-14Cr-4.5Al-2 W-0.35HfH1.98–0.6Y2Ti2O7, wt%) are made of Y2Ti2O7 (semi-coherent with the matrix and about 10 nm) and HfO2 (incoherent with the matrix and about 26 nm). The size of oxide dispersoid in FHYT-0.6 is reduced to 8.8 nm and the number density is greatly increased to 9.4 × 1023 m−3 compared with FTYT-0.6 (Fe-14Cr-4.5Al-2 W-0.35Ti-0.6Y2Ti2O7, wt%) and FTY-0.6 (Fe-14Cr-4.5Al-2 W-0.35Ti-0.6Y2O3, wt%). The tensile strength at room temperature of FHYT-0.6 is 1194 MPa, which is 24.1 and 14.1% higher than the FTY-0.6 and FTYT-0.6, respectively. Our work has proved that the mechanical properties of the alloy can be significantly improved by adding Y2Ti2O7 and HfH1.98 NPs, which provides a new idea for manufacturing high-performance ODS steels.

Effective parameters on the combustion performance of coated aluminum hydride nanoparticles: A molecular dynamics study

In this study, the combustion of coated aluminum hydride nanoparticles (NPs) was investigated using molecular dynamics (MD) simulation. The relationship between the type of atomic coating, initial temperature, and initial pressure (IP), and the thermal and combustion behavior of aluminum hydride NPs was explored. The results indicate that the ethanol atomic coating exhibited better combustion performance compared to the octyl sebacate, HTPB, and diethyl ether atomic coatings. As a result, the maximum radial distribution function (RDF) of oxygen and aluminum in the ethanol-coated structure increased to 3.81 W/m2 and 2.33, respectively, after 1 ns. Studying the effect of initial temperature, increasing it from 1000 to 1500 K, led to an increase in heat flux (HF) and maximum RDF from 3.88 W/m2 and 1.55–7.39 W/m2 and 2.84, respectively. This suggests that increasing the initial temperature improved the thermal behavior of the structures. Finally, increasing the IP from 0 to 5 bar resulted in a decrease in HF and maximum RDF from 3.28 W/m2 and 1.38–3.10 W/m2 and 1.20, respectively. Consequently, increasing the IP had no positive effects on the combustion process of the structure, and it operated more effectively at 1 bar pressure. These findings are expected to significantly enhance the thermal and combustion behavior of diverse atomic structures, which will be important given the growing usage of NPs in several sectors of industry and technology.

The effect of penetrated oxygen particles on combustion time of coated Al hydride nanoparticles in an oxygenated medium by applying molecular dynamics method via Lennard-Jones and reactive force-field potentials

Today, combustion process (CP) has been used in multifarious industries such as electricity generation, transportation, and heating due to its high energy content. Due to importance of studying CP and good performance of Al-based atomic structures, and since effect of initial temperature in range of 1100 to 1500 K on CP of coated Al hydride nanoparticle (AHNP) has not been investigated, present study investigated CP of ethanol-coated AHNP in an oxygenated and aqueous environment using molecular dynamics (MD) simulation. This simulation done with LAMMPS software. The Verlet algorithm used to determination of physical quantities such as space and velocity. The system temperature adjusted with nose-Hoover thermostat. The potentials of Lennard-Jones (LJ) and reactive force-field (RexFF) used to quantify interactions. It is seen that after 1 ns (equilibration time), temperature of both simulated structures in aqueous and oxygenated environments approach 1000 K. The PE in both simulated atomic samples (in aqueous and oxygenated environments) reaches a certain value after 1 ns, indicating simulated samples’ physical equilibrium. By adding ethanol atomic coating, temperature, and PE changes reach numerical values ​​of 1240 K and -558.33 eV, respectively; while the maximum temperature change in an aqueous and oxygenated environment reaches 1191.12 and 1246.89 K.

Molecular dynamics simulation of combustion behavior of coated aluminum hydride nanoparticles in the oxygenated medium: Effects of adding the ethanol atomic coating

This study used molecular dynamics (MD) simulations to investigate the coated aluminum hydride nanoparticles' thermal, and combustion behavior in an oxygenated medium. Thermal and combustion manner in the presence of two ethanol and nickel atomic coatings were studied. The system's thermal and combustion manners were studied by temperature changes, potential energy changes, penetrated oxygen, heat flux changes, and radial distribution functions. The penetrated atoms showed the combustion process. The greater number of oxygen atoms penetrated, showed the improvement in the combustion process occurred in a shorter time. The results showed that the duration of combustion process in the presence of ethanol atomic coating occurred in a shorter time than nickel atomic coating. Furthermore, the flowing heat flux, and the number of oxygen atoms penetrating atomic structure were higher in the ethanol-coated structure. Therefore, ethanol atomic coating showed better thermal, and combustion behavior. Then, combustion process was studied by adding the percentage of ethanol atomic coating to 12%. By increasing atomic percentage of ethanol coating to 12%, heat flux and number of oxygen penetrated increased from 3.88 to 172 to 7.01 W/m2 and 225, respectively. Finally, radial distribution function showed that increasing the coating percentage increased number of infiltrated oxygen atoms.

Impact of Polymers on Magnesium-Based Hydrogen Storage Systems.

In the present scenario, much importance has been provided to hydrogen energy systems (HES) in the energy sector because of their clean and green behavior during utilization. The developments of novel techniques and materials have focused on overcoming the practical difficulties in the HES (production, storage and utilization). Comparatively, considerable attention needs to be provided in the hydrogen storage systems (HSS) because of physical-based storage (compressed gas, cold/cryo compressed and liquid) issues such as low gravimetric/volumetric density, storage conditions/parameters and safety. In material-based HSS, a high amount of hydrogen can be effectively stored in materials via physical or chemical bonds. In different hydride materials, Mg-based hydrides (Mg–H) showed considerable benefits such as low density, hydrogen uptake and reversibility. However, the inferior sorption kinetics and severe oxidation/contamination at exposure to air limit its benefits. There are numerous kinds of efforts, like the inclusion of catalysts that have been made for Mg–H to alter the thermodynamic-related issues. Still, those efforts do not overcome the oxidation/contamination-related issues. The developments of Mg–H encapsulated by gas-selective polymers can effectively and positively influence hydrogen sorption kinetics and prevent the Mg–H from contaminating (air and moisture). In this review, the impact of different polymers (carboxymethyl cellulose, polystyrene, polyimide, polypyrrole, polyvinylpyrrolidone, polyvinylidene fluoride, polymethylpentene, and poly(methyl methacrylate)) with Mg–H systems has been systematically reviewed. In polymer-encapsulated Mg–H, the polymers act as a barrier for the reaction between Mg–H and O2/H2O, selectively allowing the H2 gas and preventing the aggregation of hydride nanoparticles. Thus, the H2 uptake amount and sorption kinetics improved considerably in Mg–H.

Atomic coatings effects on the combustion of aluminium hydride nanoparticles dispersed in liquid oxygen: Molecular dynamics simulation for the oxygenated environments

In the present study, the combustion of the AlH3 structures coated with various structures in a liquid oxygen environment was examined. This paper examined the combustion process (CP) of coated AlH3 nanoparticles (NPs) with changes in the number of permeated oxygen atoms into AlH3 NPs, temperature, and potential energy using the molecular dynamics (MD) approach. And the temperature and combustion time changes were investigated with two potential functions of LJ/EAM and Reaxff. The results show that temperature converges to 1097, 1117, and 1103 K for HTPB, Dioctyl sebacate, and Diethyl ether atomic coating, respectively (with LJ/EAM force field) after the CP. Also, the temperature converged to 1007 K, 1018 K, and 1012 K for HTPB, Dioctyl sebacate, and Diethyl ether, respectively, using the ReaxFF force field. Also, by adding these atomic coatings, the potential energy rates increase, and the combustion time of the simulated structure decreases. Numerically, adding the atomic coatings of HTPB, Dioctyl sebacate, and Diethyl ether, the potential energy reached −502.11, −495.21, and −529.17 eV. Among the studied atomic coatings, the simulated sample with dimethyl ether coating has the shortest combustion time (1.25 ns). Also, with the addition of Diethyl ether atomic coatings, the number of permeated oxygen atoms increases from 107 to 165. As the atomic coating is added to the primary NP, the amount of adsorbent exerted to the atoms of oxygen in the structures increases; this procedure reasons more oxygen to penetrate the overall structure of the NP. Generally, The outcomes display that adding atomic coatings to simulated structures improves combustion behaviour.

Molecular dynamics simulation the effect of initial pressure on the phase transition performance of coated AlH3 nanoparticles in the presence of an oxygenated medium

In this study, molecular dynamics (MD) simulation is used to study the combustion behavior of coated aluminium hydride (CAH) nanoparticles with ethanol in the presence of an oxygenated medium. The present research investigates the change in the physical quantities such as penetrating oxygen atoms into aluminium hydride (AlH3) nanoparticles, temperature (T) changes, and potential energy (Pe). Lennard-Jones and EAM potential functions are used in this study. The results show that the Pe in the presence of an ethanol atomic coating is −569 eV, the maximum (Max) T is 1322 K, and the number of penetrating oxygen atoms reaches 175. On the other hand, the combustion process in the simulated structure is investigated by increasing initial pressure (P) to the ethanol-coated sample. The results show that with increasing P, the max T decreases from 1102 to 1066 K, and the max Pe increases from −412 eV to −388 eV. The number of penetrated atoms (N) is reduced from 162 to 150, respectively. As a result, the combustion process of CAH nanoparticles is reduced by increasing the P. Since the potential function plays an essential role in MD simulations, the max T and number of penetrated oxygen atoms are investigated with the ReaxFF potential function for a better investigation of the combustion process in the simulated structure. The numerical results show that the max T decreases to 1041 K and the N-oxygen in the simulated structure decreases to 148 atoms with increasing P. The results of MD simulations are sufficiently valid and can be generalized to experimental cases.

How Much Structural Information Could Be Extracted from XANES Spectra for Palladium Hydride and Carbide Nanoparticles

How Much Structural Information Could Be Extracted from XANES Spectra for Palladium Hydride and Carbide Nanoparticles

Phase transition in aluminum hydride nanoparticles coated with different atomic structures using molecular dynamics method

One of the most important new structures is nanofluids with acceptable performance in various processes. Due to the increasing use of nanoparticles in various parts of industry and technology, in this study, the phase transition in aluminum hydride nanoparticles coated with different atomic structures was investigated by the molecular dynamics method. In this study, to calculate the structure potential, the potentials of Lennard-Jones, EAM, and Coulomb were used. In this research, some parameters such as temperature and total energy equilibrium in the simulated sample, the influence of nanoparticles on heat flux changes, the effect of nanoparticles on phase transition time, and the effect of nanoparticles on atomic stability time are examined. The MD simulation results show that the heat flux in the atomic samples enhances with more nanoparticles in atomic structures. Also, with aluminum hydride nanoparticles with a numerical value of 5% into the simulated structures, the phase transition time in the simulated water-based fluid reaches 4.95 ns. The results of this study are expected to be effective in improving phase transition behavior in related processes.