High Desorption Research Articles

A novel and cost-effective synthesis of magnetic zeolite 4A using kaolinite and red mud for Sr(II) removal

A novel and cost-effective approach was successfully developed for synthesizing high-performance zeolite 4A encapsulating magnetic particles (magnetic zeolite 4A) using kaolinite and red mud as raw materials via one-step combined activation-reduction and subsequent hydrothermal synthesis. The concurrent reduction of iron compounds in red mud to magnetic particles mainly composed of Fe3O4 during the thermal activation of kaolinite eliminated the need for a distinct red mud reduction process, thereby streamlining the synthesis and maximizing efficiency. The resulting product comprised highly crystalline zeolite 4A encapsulating magnetic particles derived from the red mud, avoiding oxidation and corrosion of the magnetic material in acidic solutions. A series of magnetic zeolite 4A (MZ) were obtained by introducing varying percentages of red mud and kaolinite, and their morphological, structural, magnetic and adsorption properties were investigated. The BET specific surface area of the obtained MZ-20 is 13.6 m2/g. MZ-20 (red mud: kaolinite mass percentage is 20%) displayed the maximum adsorption capacity of 172 mg/g for Sr(II). Within 1 h, 96.4% of the Sr(II) was removed. The adsorption kinetics and isotherms followed the pseudo-second-order and Langmuir models, respectively. Using a mixed 0.1 M NaCl and 0.1 M HCl solution as eluent, the magnetic adsorbent maintained high desorption and regeneration ratios along with stable magnetic properties after four adsorption-desorption cycles. In summary, the MZ-20 adsorbent exhibited high adsorption capacity, recyclability and excellent magnetic properties, making it a decontamination candidate for removing Sr(II) from radioactive wastewater.

Research on CO2 capture performance and reaction mechanism using newly tetraethylenepentamine (TEPA) + monoethanolamine (MEA) mixed absorbent for onboard application

Large–scale CO2 emissions have raised international concerns as they lead to global temperature rise. Consequently, mitigating CO2 emissions has emerged as a central focus of interdisciplinary research. Although onboard carbon capture technology proves effective in reducing a ship's CO2 emissions, challenges persist in the form of high desorption energy consumption and low CO2 loading of the absorbents. In this study, a novel polyamine–based mixed amine system based on marine engine exhaust CO2 capture technology has been developed to reduce desorption energy consumption and enhance CO2 loading. Additionally, the reaction mechanisms of CO2 with polyamine–based mixed amine were investigated using a combination of quantum chemical calculations and nuclear magnetic resonance (NMR) techniques. The results indicated that compared to monoethanolamine (MEA) with the same mass fraction, the CO2 loading of the new mixed absorbent tetraethylenepentamine (TEPA) + MEA increased by 7 % and the desorption heat duty reduced by 18.1 %. The analytical approach results showed that in the case of 7.5 wt% TEPA + 7.5 wt% MEA solution, proton transfer was predominantly governed by TEPA, whereas MEA primarily engaged in the reaction with CO2. During desorption at 368 K, the released CO2 primarily arose from HCO3− and CO32−. These findings hold academic and practical significance for the advancement of more efficient carbon capture technologies in maritime applications.

Can Microplastics Accumulate Toxic dye in Water? An adsorption-desorption Study under Different Experimental Conditions.

The adsorption/desorption of Rhodamine B (RhB) on Polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC) microplastics (MPs) was investigated in this study. The results showed that RhB adsorption on the selected MPs was fast. The adsorption coefficients (Kd) of RhB were 2036 ± 129, 1557 ± 91, and 63 ± 8.5L kg- 1 for PS, PP, and PVC, respectively. RhB adsorption on PS and PP increased with increasing temperature and decreasing ionic strength, whereas RhB adsorption on PVC showed a completely opposite trend. The binding strength of RhB on the three types of MPs was weak as demonstrated by the high total desorption percentage, which ranged from 79.59 ~ 89.39%. This study shows that PP and PS MPs can accumulate RhB in the aquatic environment and their potential combined toxic risks should be taken seriously.

Li decorated graphene like MgN4 monolayer for hydrogen storage: A first-principles approach

The rapid advancement of hydrogen storage materials possessing high storage capacity, long life-cycle, reversibility, and rapid kinetics is a trending issue. Metal decoration of a two-dimensional material is a successful method of enhancing hydrogen storage capacity. Li-decorated 2D MgN4 has been inspected as a hydrogen storage material for practical applications employing density functional theory simulations. Our findings indicate that the substrate (LiMgN4) may adsorb up to 6 molecules of H2 with a gravimetric storage capacity of 1.83 wt.%, making it a viable choice for storage medium. With an average adsorption energy of 0.21 eV per H2, hydrogen is effectively sensed by Li-augmented MgN4 monolayer. Additionally, two-sided Li-decoration is discussed with 12 H2 adsorbed on each side with a storage capacity of 6.86 wt.% with an average adsorption energy of 0.15 eV/H2. High desorption temperature confirms the effective desorption of H2 from the substrate. The Li-decorated porous MgN4 responds effectively in the adsorbate (H2) environment. The predicted adsorption energy, recovery time and desorption temperature demonstrate that LiMgN4 is an exceptional choice for energy storage devices.

Sunlight assisted highly efficient desorption of ammonia by redox graphene hybrid metal–organic framework photothermal conversion adsorbents

The capture, storage and release of NH3 play a pivotal role in sustainable energy applications. However, to simultaneously achieve high adsorption capacity and low energy desorption remains a challenge. In this work, a novel class of hybrid materials with photothermal conversion performance have been developed by doping redox graphene and metal–organic framework of MOF-303(Al). It is found that the optimized rGO@MOF-303(Al)-8% exhibits high NH3 uptake (17.0 mmol g−1) at 25.0 °C and 1.0 bar and exceptional photothermal conversion performance. Under the irradiation of simulated sunlight, its temperature can be raised to about 75 °C in 10 min. Even under direct natural sunlight irradiation, a stable equilibrium temperature of 53 °C may be achieved. Based on this excellent photothermal conversion performance, we investigated the desorption behavior of ammonia under visible light irradiation for the first time. We found that due to the breakdown of hydrogen bonds of NH3 and N-N, N–H sites of rGO@MOF-303(Al)-8% caused by the rapid rise of temperature, approximately 68% of NH3 could be effectively desorbed in 2-hour irradiation under ambient conditions. In addition, the optimized adsorbent demonstrated remarkable cycling stability. After undergoing 10 cycles, high adsorption capacity and efficient light-induced desorption of NH3 were still maintained Thus, the present study provides a novel concept for high-capacity adsorption and low-energy desorption of NH3 and other industrial gases.

Construction of C8/threonine-functionalized mesoporous silica aerogel based on mixed-mode and its adsorption properties for both anionic and cationic dyes

High adsorption and desorption efficiencies for both anionic and cationic dyes are still a challenge for adsorbents to treat dyestuffs wastewater. In this study, the C8/threonine-functionalized mesoporous silica aerogel based on mixed-mode was constructed to overcome the challenge, with properties of hydrophobicity and switchable surface charge of n-octyl and threonine groups. With methylene blue and azophloxine as cationic and anionic dye models, batch tests were conducted. The consequences proofed the adsorption process was efficient and fast, and the highest adsorption quantities for methylene blue and azophloxine were estimated as 274.30 mg/g and 152.43 mg/g, respectively. Additionally, the adsorbent showed good removal efficiency and reusability. The desorption efficiencies exceeded 97% using low concentration HCl or NaOH as eluents. Mechanism investigation proved that adsorption process relied on hydrophobicity and electrostatic interactions. These results instructed that SG-C8/Thr was a promising adsorbent with excellent adsorption and desorption efficiencies for both anionic and cationic dyes.

Nano-imaging mass spectrometry by means of high-energy laser desorption ionization (HELDI)

A calibration curve is built on points spread over a range, which is a function of the variance of the blank, instrumental error and heterogeneity.

Adsorption Mechanism of Methylene Blue on Purified Red Phosphorus and Effects of Different Temperatures on Methylene Blue Desorption

Purified red phosphorus (RP) can be used as an adsorbent. However, the adsorption mechanism and reuse ability of purified RP have not been reported. This study utilized X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy techniques (a statistical physics model and the standard molar free energy of formation) to investigate the adsorption mechanism of methylene blue (MB) by purified RP. Purification did not change commercial RP structure according to X-ray diffraction. The results showed that the adsorption process only included physical adsorption according to Fourier transform infrared spectroscopy and UV–vis diffuse reflection absorption spectra. The specific areas of commercial RP and purified RP were 0.02 cm3/g and 5.27 cm3/g, respectively. Thus, purified RP has a higher adsorption capacity compared with commercial RP. A statistical physics model showed that, as the temperature increased from 288 to 308 K, the qe, Dm and qsat of purified RP for MB increased from 179.87, 0.824 and 0.824 to 303.26 mg/g, 1.497 mol/kg and 1.497 mol/kg, respectively. The fitted values of ΔrSmθ, ΔrHmθ and ΔrGmθ were 104.38 J·mol−1·K−1, −2.7 × 103 J·mol−1 and negative, respectively. Thus, according to adsorption energy, the adsorption of MB by purified RP was a spontaneous process, which was mainly driven by entropy increasing. Compared with neutral dye, the purified RP had higher adsorption ability for the cationic dye and anionic dye. As the purified RP dose increased from 30 to 150 mg, the adsorption capacity of purified RP increased. However, as the MB concentration and pH increased, the adsorption capacity of purified RP decreased. The purified RP had excellent reuse ability and high temperature desorption can be applied to obtain its reuse ability.

Pengaruh Variasi Waktu Milling terhadap Temperatur Nanokomposit Fe3O4 - MgH2 sebagai bahan baku katalis pada Tabung Hydrogen Storage

Metal materials can be used in renewable energy with future technologies for safe hydrogen storage media. Metal hydrides are a safe and effective way to store hydrogen for vehicle applications. Due to its high capacity in mass and volume for hydrogen storage, metal hydrides are currently the subject of intense research. However, the thermodynamic properties of magnesium hydride (MgH2) produce moderate temperatures, during the hydrogen desorption reaction reaching about 3000C to 4150C at 1 bar. The thermodynamic properties of high MgH2 cause the desorption temperature to also increase. The enthalpy produces high desorption (about 74 KJ/mol H2). In addition, the process of transforming magnesium into magnesium hydride takes a long time, (for 60 hours). From the results of the study, iron sand, a material from nature, which has been extracted into Fe3O4 powder, is used as a catalyst. This is done to improve the absorption properties and reaction kinetics of hydrogen storage materials based on MgH2, namely magnetite Fe3O4. The yield of Magnetite Extraction (Fe3O4) from iron sand is 85% purity, compared to the purity of Iron sand before extraction, which is 81%. Mechanical alloying methods are used to process MgH2-Fe3O4 samples, with different milling times and different catalysts.

A strategy for deep removal of Cu from Ni anolyte based on the ion-exchange method

The sulfide precipitation method has been one of the major strategies used for the removal of Cu from the Ni anolyte. However, the high cost and short shelf-life of the Cu removal agents have consistently posed problems in the practical industrial use of the Ni anolyte purification process. In the present study, a new method for removing Cu from Ni anolyte based on ion exchange is proposed to address the drawbacks of the current sulfide precipitation method. Through isothermal adsorption curve analysis, thermodynamic studies, kinetic studies and cross-sectional SEM-EDS analyses, it was found that the selectivity difference of D850 resin to Cu2+ and Ni2+ is dependent on iminodiacetic acid forming a triple bond with Cu2+ while forming a double bond with Ni2+ in the removal of Cu from a Ni anolyte. The resin dynamic adsorption experiments showed that the fixed-bed ion exchange process is quite similar to the cascade solvent extraction process. The investigations into resin regeneration found that the desorption of Cu2+ and Ni2+ was adequately completed for static desorption when the desorbent concentration was than more 1 mol/L for 60 min. The experiments on D850 resin desorption showed that the desorption equilibrium time, desorbent concentration, and desorption temperature were key factors affecting the desorption of Cu2+ and Ni2+. The dynamic desorption process revealed that a high concentration of hydrochloric acid and a high flow rate could accelerate the desorption process, concentrating the outflow peak and facilitating the collection of Cu2+ and Ni2+. This Cu removal method based on resin ion exchange utilizes the different characteristics of iminodiacetic acid adsorbing Cu and Ni to achieve efficient Cu removal from the Ni anolyte and its recycling. This method is superior to the current method due to its high selectivity, fast adsorption, high desorption rate, and high Cu–Ni ratio of the desorption solution.

Analysis of sorption/desorption of cadmium and lead in the legal amazon soils

Sorption and desorption tests were carried out for competitive and non-competitive systems with isotherms to verify the presence of Cd and Pb in soils. The soils investigated were: (i) with natural content of organic matter and (ii) with residual content of organic matter. Hydrated nitrate salts of Cd and Pb diluted in 0.01 M calcium nitrate solution in six concentrations were used for the Cd solutions and, for the solutions of Pb, five concentrations. For multielement solutions, mixtures of the simple Cd and Pb solutions in a 1:1 ratio were used. The results of the first stage tests (i) showed good adjustments of the experimental data to the isotherms of Langmuir, Freundlich and Linear, which did not occur for the tests in stage (ii). According to the tests (i), the organic matter was the soil attribute of dominant influence in the sorting mechanisms. The parameters Qo and Kd were adequate to evaluate the adsorption of the studied metals, especially Cd. In step (ii), there was a significant increase in metal retention, especially for element Pb in the samples of Haplic Cambisol (AM) and Red-Yellow Latosol1 (RO), justified by the combined action of (1) increasing the surface area of the mineral fraction, previously covered by organic matter; and (2) increase in soil pH. The Cd element was more bioavailable in relation to the Pb. This was confirmed by the high desorption values observed for Cd. The samples of Haplic Cambisol and Red-Yellow Latosol demonstrated greater capacity to retain Cd and Pb.

Effect of d-block metals (M = Ti, Zr, Hf) decorated fullerenes M@C60 as sensor nanostructured materials for volatile organic compounds (VOCs): Approach from computational study

Volatile organic compounds (VOCs) are organic substances that readily evaporate into the atmosphere at room temperature, posing a regular exposure risk to humans. These compounds are associated with various environmental issues, including stratospheric ozone layer depletion, ground-level smog formation, climate change, sick building syndrome, plant decay, atmospheric toxicity, and potential carcinogenic effects on human health. In this study, we utilized ab-initio calculations based on density functional theory (DFT) at the B3LYP-GD3(BJ)/Def2-SVP method to examine how the functionalization of C60 fullerene with Ti, Hf, and Zr transition metals affects its sensing capabilities for volatile organic compounds, specifically methylcyclopentane (MCP), propanone (PPN), and benzene (BZN). The maximum adsorption energy of the transition metal decorated nanocages was recorded at 73.689 kcal/mol corresponding to PPN_Zr@C60 in tandem with the least energy gaps indicating higher conductivity of the PPN_Zr@C60 nanocage with the short bond distance of 1.929 Å for (Zr – O) interaction. The adsorption energy value proposes the adsorption of the volatile organic compound on the Ti, Hf, and Zr transition metal decorated C60 fullerene following the order BZN_Hf@C60 < BZN_Ti@C60 < PPN_Zr@C60. The studied systems possess a relatively high desorption time and they follow the increasing trend – BZN_Hf@C60 < MCP_Hf@C60 < MCP_Zr@C60 < MCP_Ti@C60 < PPN_Hf@C60 < BZN_Zr@C60 < BZN_Ti@C60 < PPN_Ti@C60 < PPN_Zr@C60. The results account that Zr@C60 possesses the highest desorption time and adsorption energy, hence more apposite for detecting the studied VOCs. It also divulges in Hf@C60 contains the least desorption time and least adsorption energy, therefore is not suitable for the detection as it basically portrays the least affinity for the adsorbed VOCs molecule. These results indicate that the VOC transition metal functionalized Ti@C60 and the Zr@C60 are excellent sensors for the effective detection and adsorption of volatile organic compounds which may be useful for environmental protection and the safeguard of human health.

Combustion derived carbon with ultrahigh-mesoporosity and moderate surface affinity towards reversible low-volatile gas capture

Capturing naphthalene as a valuable chemical from waste gases via adsorption on porous sorbent materials is a promising approach to tackle such an environmental health issue with additional economic benefits. However, very few sorbents have simultaneously high adsorption capacity and good regenerability for the large-molecular and low-volatile naphthalene. Here we attempt to address this challenge by integrating key fabrication elements of a layer-by-layer network, rational mesoporosity, and highly reversible sites into a carbonaceous adsorbent (ECSC) using a facile and fast eruptive solution combustion synthesis method. Adsorption breakthrough and temperature-programmed desorption experiments show that the ECSC achieves all-round superior naphthalene capture performance with unprecedented high capacity, fast kinetics, and low desorption energy. The combination of in situ DRIFTS, XPS, and DFT calculations reveals the moderate adsorption affinity of mitigated π–π stacking bonding between tilted naphthalene molecule and surface pyridinic N. This work affords new insights for designing next-generation adsorbents for naphthalene removal and presents a way of overcoming the adsorption–desorption dilemma for gas purification.

Novel diamine DMAPA-sulfolane-water biphasic absorbent for equimolar CO2 absorption: Performance and mechanisms

A novel diamine-based biphasic absorbent, 3-(Dimethylamine)-1-propylamine (DMAPA)-Sulfolane-Water, was proposed for equimolar CO2 absorption with high absorption–desorption efficiency. To optimize the CO2 capture performance of the proposed DMAPA-Sulfolane-Water biphasic absorbents, the phase separation experiments and the absorption–desorption cyclic experiments were conducted. The results indicated that the DMAPA-Sulfolane-Water biphasic absorbent could realize a liquid–liquid phase separation performance after CO2 absorption with sulfolane as the phase splitter and generate a CO2-rich upper-phase and a CO2-lean lower-phase. An equimolar absorption (1.023 mol CO2 /mol DMAPA), a high initial absorption rate (0.106 mol/(L*min)), a low viscosity (10.96 mPa.s) and a high CO2 loading (3.68 mol/L) of the CO2-rich upper-phase, a high desorption efficiency (92 %), and high cyclic stability were obtained due to the interaction of the intramolecular primary and tertiary amino groups in DMAPA. The minimum volume percentage of the rich phase was as low as 32 % of the total volume. In addition, temperature was confirmed to be an essential factor in the absorption and desorption process. The species in the two phases after CO2 absorption were identified by 13C NMR, not only further identifying the CO2-rich upper-phase but also revealing the mechanism of equimolar absorption by the DMAPA-Sulfolane-Water biphasic absorbents because of the high carbon peak of carbamic acid (DMAPACOOH) in the upper-phase. The quasi-salting out effect and the improved polarity of the solvents were proved to trigger the phase separation.

Layered double hydroxide-derived Mg2Ni/TiH1.5 composite catalysts for enhancing hydrogen storage performance of MgH2

Developing efficient catalysts is of great significance in improving the sluggish kinetics and high desorption temperature of MgH2 hydrogen storage material. Here, ultrathin NiTi-layered double hydroxide (NiTi-LDH) nanosheets are used as precursors to prepare Mg2Ni/TiH1.5 composite catalysts to improve the hydrogen storage properties of MgH2. The variation of Ni/Ti ratio in LDH plays an important role in regulating the composition, morphology and distribution of Mg2Ni/TiH1.5 catalysts, which significantly affect their synergistic catalytic effect. Mg2Ni/TiH1.5 composite catalyst exhibits significantly improved catalytic performance compared with conventional Ni-, Ti- and Ni/Ti-based catalysts. The optimal MgH2/Mg2Ni/TiH1.5 system shows a significantly reduced desorption temperature of 212 °C which is 133 °C lower than that of pure MgH2 (345 °C), and can release 5.97 wt% hydrogen within 300s at 300 °C. Further mechanism analysis reveals that the unique flaky morphology and suitable composition of Ni/Ti LDH can significantly enhance the synergistic effect of Mg2Ni and TiH1.5, which promotes the fracture of the HH and Mg-H bonds.

Confined Cu-OH single sites in SSZ-13 zeolite for the direct oxidation of methane to methanol

The direct oxidation of methane to methanol (MTM) remains a significant challenge in heterogeneous catalysis due to the high dissociation energy of the C-H bond in methane and the high desorption energy of methanol. In this work, we demonstrate a breakthrough in selective MTM by achieving a high methanol space-time yield of 2678 mmol molCu−1 h−1 with 93% selectivity in a continuous methane-steam reaction at 400 °C. The superior performance is attributed to the confinement effect of 6-membered ring (6MR) voids in SSZ-13 zeolite, which host isolated Cu-OH single sites. Our results provide a deeper understanding of the role of Cu-zeolites in continuous methane-steam to methanol conversion and pave the way for further improvement.

Organic-Solvent-Resistant Polyimide/Hydroxyapatite Mixed Matrix Membranes for Lysozyme Adsorption.

This work reports new mixed matrix membranes (MMMs) for the adsorption of enzymes from organic solvents. In this work, polyimide/hydroxyapatite (PI/HAP) MMMs were prepared via phase inversion method and further crosslinked with 3-aminopropyl triethoxysilane (APTES). The chemical and structural stability of the crosslinked PI/HAP MMMs were improved and applied for lysozyme (LZ) adsorption in organic solvent. PI/HAP MMMs were crosslinked by changing the 3-aminopropyltriethoxysilane (APTES) concentration and crosslinking time. The optimal APTES crosslinking condition for PI/HAP MMMs is 6% of concentration for 8 h. The LZ adsorption performance was studied by changing solvent types. PI/HAP MMMs possessed a high LZ adsorption in organic-solvent-aqueous solutions, and the LZ adsorption capacity reached 34.1 mg/g. The MMMs had a high desorption capacity and recovery ability. The MMMs maintained 60% of their adsorption capacity and 58% of their desorption at the fourth cycle of adsorption and desorption. The MMMs provided a new technology for the purification and separation of enzymes or proteins by MMMs in organic solvents.

Compositionally complex doping for low-V Ti-Cr-V hydrogen storage alloys

Ti-V-based BCC solid solution alloys, represented by Ti-Cr-V alloys, are considered as promising hydrogen storage materials due to their high hydrogen storage capacity (over 4 wt%) at room temperature. However, the difficult activation, low effective hydrogen desorption capacities, poor P-C-T plateau characteristics, and high cost remain significant problems for their practical applications. Herein, we present a new compositionally complex (high-entropy) doping strategy which was used to successfully fabricate a low-cost “Laves phase related BCC solid solution”, TiCrV0.7(Nb0.2Fe0.2Co0.2Ni0.2Mn0.2)0.2, that exhibits excellent activation performance and high effective hydrogen desorption capacity (Ce1atm: 2.21 wt%). The main BCC phase ensures high hydrogen storage capacity, while the minor secondary C14 phase plays a catalytic role and thus improves the hydrogen absorption kinetics. Furthermore, we confirmed that there is a synergistic effect of Nb, Fe, Co, Ni, and Mn elements in improving hydrogen storage performance. The dehydrogenation enthalpy ΔH of the heat-treated TiCrV0.7(Nb0.2Fe0.2Co0.2Ni0.2Mn0.2)0.2 is 37.5 kJ mol−1, which is significantly lower than previously reported Ti-Cr-V based systems, revealing a significant tendency towards easier dehydrogenation with high-entropy doping. This work offers a new alloying method for improving the hydrogen storage performance of hydrogen storage alloys.

Uranium recovery from weakly acidic wastewater using recyclable γ-Fe2O3@meso-SiO2

U(VI)-containing acidic wastewater produced from uranium mining sites is an environmental hazard. Highly efficient capture of U(VI) from such wastewater is of great significance. In this study, a mesoporous core–shell material (i.e. γ-Fe2O3@meso-SiO2) with magnetically and vertically oriented channels was rationally designed through a surfactant-templating method. Batch experiment results showed that the material had an efficiency level of >99.7% in removing U(VI) and a saturated adsorption capacity of approximately 41.40 mg/g, with its adsorption reaching equilibrium in 15 min. The U(VI) adsorption efficiency of the material remained above 90% in a solution with competing ions and in acidic radioactive wastewater, indicating its ability to selectively adsorb U(VI). The material exhibited high adsorption efficiency and desorption efficiency in five cycles of desorption and regeneration experiments. According to the results, the mechanism through which γ-Fe2O3@meso-SiO2 adsorbs U(VI) was dominated by chemical complexation and electrostatic attraction between these two substances. Therefore, γ-Fe2O3@meso-SiO2 is not only beneficial to control the environmental migration of uranium, but also has good selective adsorption and repeated regeneration performance when used to recover U(VI) from weakly acidic wastewater in uranium mining.

Enhanced hydrogen storage properties of Ti40-xV45Zr15Crx alloys by dual-phase nanostructures of eutectic and spinodal decomposition

Multi-principal elements alloys (MPEAs) with body center cubic (BCC) structure have shown great potential in hydrogen storage. However, the multi-cycle activation process and the high desorption temperature have inhibited their applications. In this study, the Ti40-xV45Zr15Crx (x = 1, 2, 3 at. %) alloys with three different BCC phases are synergized, and high hydrogenation capacities of over 2 wt% are achieved in the first hydrogen absorption. Owing to the formation of spinodal decomposition nanostructure in Ti38V45Zr15Cr2 alloy, 90 % of total hydrogen capacity is reached in 30s at 250 °C under 1 MPa H2, which indicates no incubation time is needed for activation. The Ti38V45Zr15Cr2 alloy also shows the highest reversible hydrogen storage capacity with fastest kinetics at 200 °C. The hydrogenation reaction is controlled by the 1D diffusion process of H atoms according to JMAK model. The spinodal decomposition structure can accelerate the decomposition of H2 molecules and the diffusion of H atoms by providing extra energy from large lattice distortion. The high-density interfaces in nano-eutectic structure can serve as active sites for the nucleation of hydrides and fast paths for the diffusion of H atoms.