Browsing by Author "Mohammad Abu Shaz"

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A facile synthesis of high entropy alloy nanoparticles and notable catalytic activity for methylene blue degradation
(Elsevier B.V., 2025) Yogesh Kumar Yadav; Sarita S. Yadav; Mohammad Abu Shaz; Thakur Prasad Yadav
In this study, mechanical ball milling has been used to synthesize a nanocrystalline Al-Cu-Fe-Ni-Ti high-entropy alloy (HEA) through controlled composition and processing parameters. Using hexane as the process control agent, the milling has been carried out in a high-energy attritor ball mill at 400 rpm for 40 h with a 40:1 ball-to-powder ratio. The development of a single-phase BCC structure with a lattice parameter of 0.289 nm has been verified by X-ray diffraction investigation. Furthermore, when tested for methylene blue degradation, its catalytic performance resulted in a 32 % decrease in absorbance at 664 nm in 20 min, with degradation continuing for 240 min. © 2025 Elsevier B.V.
Achievement of excellent hydrogen sorption through swift hydrogen transport in 1:2 Mg(NH2)2–LiH catalyzed by Li4BH4(NH2)3and carbon nanostructures
(Elsevier Ltd, 2022) Vivek Shukla; Thakur Prasad Yadav; Mohammad Abu Shaz
The present studies deal with the catalytic character of carbon nanostructure (Graphene (Gr) and single-wall carbon nanotubes (SWNTs), and their composite versions) on the hydrogen sorption behavior of 1:2 Mg(NH2)2–LiH/Li4BH4(NH2)3. The inclusion of an optimal quantity of 2 wt% SWNTs in Mg(NH2)2–2LiH/Li4BH4(NH2)3 resulted in superior hydrogen sorption over 2 wt% Gr and 2 wt% of (Gr and SWNT) composite. The onset desorption temperature for SWNTs catalyzed Mg(NH2)2–2LiH/Li4BH4(NH2)3 is 108 °C which is 32 °C, 44 °C lower compared to Gr catalyzed Mg(NH2)2–2LiH/Li4BH4(NH2)3 and uncatalyzed Mg(NH2)2–2LiH/Li4BH4(NH2)3 respectively. The de/re-hydrogenation kinetics of the SWNT catalyzed sample has been found to be 4.02 wt% and 4.63 wt% within 15min at 170 °C and 7 MPa H2 pressure, correspondingly. The activation energy for SWNT catalyzed Mg(NH2)2–2LiH/Li4BH4(NH2)3 has been found to be 69.75 kJ/mol. The SWNT catalyzed Mg(NH2)2–2LiH/Li4BH4(NH2)3 shows good cyclic stability (almost no degradation) up to 10 cycles. The better hydrogen sorption for SWNTs is attributed to the ballistic transport of hydrogen atoms within and across the amide/hydride matrix. In contrast, Gr sheets agglomerate, which adversely affects hydrogen sorption from Gr and Gr+SWNT composites. A hydrogen sorption mechanism has been proposed based on structural, microstructural, Fourier-transform infrared spectroscopy, and Raman characterization results. © 2022 Hydrogen Energy Publications LLC
Al–Cu–Fe–Ni–Ti high entropy alloy nanoparticles as new catalyst for hydrogen sorption in MgH2
(Elsevier Ltd, 2024) Yogesh Kumar Yadav; Mohammad Abu Shaz; Thakur Prasad Yadav
The earth's abundance of magnesium hydride (MgH2), along with its favorable qualities like high capacity, excellent reversibility, and cost-effectiveness under mild hydrogenation conditions, make it a potential material for hydrogen storage. Its practical applicability is limited by unfavorable thermodynamics and kinetics, despite these advantages. In this work, we investigate the use of a leached form of the mechanically alloyed high entropy alloy (HEA) Al–Cu–Fe–Ni–Ti as a catalyst to improve the hydrogen storage capabilities of MgH2. The onset desorption temperature of MgH2 is significantly reduced from 360 °C (for as-received MgH2) to 200 °C when catalyzed by the previously stated HEA catalyst. In addition, the catalyst exhibits enhanced kinetics, as it can absorb around 6.2 wt. % in just 2.3 min. at 300 °C and 15 atm of hydrogen pressure, and desorb approximately 5.8 wt. % in 3.8 min. When compared to other known catalysts, these results show some of the lowest desorption temperatures for MgH2. Furthermore, MgH2 catalyzed by the leached form of Al–Cu–Fe–Ni–Ti HEA exhibits good cyclic stability for up to 21 cycles, with just a small variation of about ∼0.02 wt. %. A thorough analysis using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy have been carried out. We suggest a workable catalytic mechanism for the high entropy alloy Al–Cu–Fe–Ni–Ti on MgH2 based on these findings. © 2024 Hydrogen Energy Publications LLC
Al–Cu–Fe–Ni–Ti high entropy alloy nanoparticles as new catalyst for hydrogen sorption in MgH2
(Elsevier Ltd, 2025) Yogesh Kumar Yadav; Mohammad Abu Shaz; Thakur Prasad Yadav
The earth's abundance of magnesium hydride (MgH2), along with its favorable qualities like high capacity, excellent reversibility, and cost-effectiveness under mild hydrogenation conditions, make it a potential material for hydrogen storage. Its practical applicability is limited by unfavorable thermodynamics and kinetics, despite these advantages. In this work, we investigate the use of a leached form of the mechanically alloyed high entropy alloy (HEA) Al–Cu–Fe–Ni–Ti as a catalyst to improve the hydrogen storage capabilities of MgH2. The onset desorption temperature of MgH2 is significantly reduced from 360 °C (for as-received MgH2) to 200 °C when catalyzed by the previously stated HEA catalyst. In addition, the catalyst exhibits enhanced kinetics, as it can absorb around 6.2 wt. % in just 2.3 min. at 300 °C and 15 atm of hydrogen pressure, and desorb approximately 5.8 wt. % in 3.8 min. When compared to other known catalysts, these results show some of the lowest desorption temperatures for MgH2. Furthermore, MgH2 catalyzed by the leached form of Al–Cu–Fe–Ni–Ti HEA exhibits good cyclic stability for up to 21 cycles, with just a small variation of about ∼0.02 wt. %. A thorough analysis using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy have been carried out. We suggest a workable catalytic mechanism for the high entropy alloy Al–Cu–Fe–Ni–Ti on MgH2 based on these findings. © 2024 Hydrogen Energy Publications LLC
Development and Demonstration of Air Stable rGO-EC@AB5 Type Hydrogenated Intermetallic Hybrid for Hydrogen Fuelled Devices
(Wiley-VCH Verlag, 2017) Ashish Bhatnagar; Bipin Kumar Gupta; Prashant Tripathi; Ayfer Veziroglu; Michael Sterlin Leo Hudson; Mohammad Abu Shaz; Onkar Nath Srivastava
Hydrogen is a promising alternative energy vector, but its use at an appropriate site requires storage, which is a crucial aspect. Hydrogen storage (HS) in the form of metal hydrides represents an attractive possibility, and is being investigated worldwide. La(Ni0.95Fe0.05)5 (LNF) has achieved significant attention as a HS media due to its suitable thermodynamics. However, its use as an effective storage material is hindered due to burning of hydrogenated LNF (LNFH) on exposure to air. The pristine LNFH catches fire rapidly on exposure to atmosphere. Here, a breakthrough strategy is demonstrated for design of hydrogenated air-stabilized hybrid material by encapsulating LNF inside reduced graphene oxide-ethyl cellulose. This novel hybrid material does not ignite upon exposure to air. This proposed hybrid material could be the ultimate choice for air-stable and safe storage for fuel cell/internal combustion engine-based vehicles. Further, the effectiveness of this hydrogen storage material is demonstrated for fuel cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Enhanced hydrogen absorption and desorption properties of MgH2 with graphene and vanadium disulfide
(Elsevier Ltd, 2023) Satish Kumar Verma; Mohammad Abu Shaz; Thakur Prasad Yadav
Magnesium hydride (MgH2) is the most prominent carrier for storing hydrogen in solid-state mode. However, their slow kinetics and high thermodynamics become an obstacle in hydrogen storage. The present study elaborates on the catalytic effect of graphene (Gr) and vanadium disulfide (VS2) on MgH2 to enhance its hydrogen sorption kinetic. The temperature-programmed desorption study shows that the onset desorption temperature of MgH2 catalyzed by VS2 and MgH2 catalyzed by Gr is 289 °C and 300 °C, respectively. These desorption temperatures are 87 °C and 76 °C lower than the desorption temperature of pristine MgH2. The rapid rehydrogenation kinetics for the MgH2 catalyzed by VS2 have been found at a temperature of 300 °C under 15 atm H2 pressure by absorbing ∼4.04 wt% of hydrogen within 1 min, whereas the MgH2 catalyzed by Gr takes ∼3 min for absorbing the same amount of hydrogen under the similar temperature and pressure conditions. The faster release of hydrogen was also observed in MgH2 catalyzed by VS2 than MgH2 catalyzed by Gr and pristine MgH2. MgH2 catalyzed by VS2 releases ∼2.54 wt% of hydrogen within 10 min, while MgH2 catalyzed by Gr takes ∼30 min to release the same amount of hydrogen. Furthermore, MgH2 catalyzed by VS2 also persists in the excellent cyclic stability and reversibility up to 25 cycles. © 2022 Hydrogen Energy Publications LLC
Facile synthesis of M2(m-dobdc) (M = Fe and Mn) metal-organic frameworks for remarkable hydrogen storage
(John Wiley and Sons Inc, 2022) Satish Kumar Verma; Mohammad Abu Shaz; Thakur Prasad Yadav
Metal-organic frameworks (MOFs) are emerging as promising candidates for hydrogen storage material because of their porosity and adjustable hydrocarbon structures coordinated with the metal element. Present work explore the synthesis of M2(m-dobdc) (M = Fe and Mn; m-dobdc4− = 4,6-dioxido-1,3-benzenedicarboxylate) metal-organic frameworks via solvothermal method for the purpose of hydrogen storage application. The X-ray diffraction, transmission electron microscope, scanning electron microscope, energy dispersive X-ray analysis, and nuclear magnetic resonance spectroscopic studies have been done to ensure the synthesized material is M2(m-dobdc) (M = Fe and Mn) MOFs. The Brunauer-Emmett-Teller (BET) analysis reveals the average pore size of 36.271 nm for Mn2(m-dobdc) MOF whereas the average pore size for fe2(m-dobdc) MOF was found to be 2.1992 nm. The as-prepared MOF samples are in the mesoporous range based on pore size distribution (internal pore diameter greater than 2 nm) with spherical pore geometry. Hydrogen storage studies shows that Fe2(m-dobdc) has a hydrogen storage capacity of 0.18 wt% at ambient temperature (30°C) under 100 atm H2 pressure, whereas the hydrogen storage capacity for Mn2(m-dobdc) is 1.38 wt% under identical conditions of temperature and pressure. The hydrogen storage capacity at liquid nitrogen temperature (−196°C) under 100 atm H2 pressure for Fe2(m-dobdc) and Mn2(m-dobdc) is 4.31 and 8.21 wt%, respectively. © 2022 John Wiley & Sons Ltd.
Formation of B2 phase and its stability in equiatomic Al-Cu-Fe-Ni-Ti high entropy alloy
(Elsevier B.V., 2024) Yogesh Kumar Yadav; Mohammad Abu Shaz; Nilay Krishna Mukhopadhyay; Thakur Prasad Yadav
In the present investigation, we synthesized a single-phase high-entropy alloy in Al-Cu-Fe-Ni-Ti system by melting of the individual metals using a radiofrequency induction furnace under an argon environment. The as-synthesized alloy showed the formation of a B2-type ordered phase with a lattice parameter of 0.289 nm. The mechanical stability of this single phase high-entropy alloy was investigated under high-energy ball milling. The milling was performed at a speed of 400 rpm for 10, 20, and 40 h under a hexane medium with a ball-to-powder ratio of 40:1. The formation of nano crystallites (∼ 10 nm sizes) body centered cubic (BCC) phase (disordered B2) has been observed after 40 h of ball milling, which has been confirmed by X-ray diffraction and transmission electron microscopic investigation. The equiatomic Al-Cu-Fe-Ni-Ti high entropy alloy structure is observed to be quite stable during mechanical milling up to 40 h; only grain refinements and lattice strain accumulation were observed with milling time. © 2024 The Authors
High entropy alloys synthesized by mechanical alloying: A review
(Elsevier B.V., 2025) Yogesh Kumar Yadav; Mohammad Abu Shaz; Nilay Krishna Mukhopadhyay; Thakur Prasad Yadav
High entropy alloys (HEAs) have attracted an intense interest from scientists, researchers, academics and industrialists in the recent times because of their exceptional physical, functional and chemical properties, which are superior to those of conventional alloys. The vast number of scientific publications has eclipsed many synthesis and production techniques being adopted for HEAs. Although the production processes for traditional alloys are well-established, a closer look must be given to the various synthesis methods used for multicomponent alloys for industrial applications. This review paper will fill this vacuum by providing a thorough and comprehensive investigation into the production of quinary, senary and higher order alloy systems in HEAs via mechanical alloying/milling. The mechanical alloying is a non-equilibrium synthesis technique that combines elemental powders through high-energy ball milling and eventually nanostructured materials can be produced. The intrinsic mechanical alloying processes of plastic deformation, cold-welding and fracture causes the changes in the size, configuration, and dispersion of the particles. As a result, a uniformly sized, finely divided powder develops; giving rise to the materials the special qualities compared to traditionally alloyed materials. Mechanical alloying is established widely for the synthesis of HEAs and other advanced materials. Through the approaches of mechanical alloying, this review paper seeks to analyze and throw light on the synthesis of HEAs especially, providing insightful information on this process and its significance for developing complex HEAs. © 2025 The Authors
Hydrogen storage properties in rapidly solidified TiZrVCrNi high-entropy alloys
(John Wiley and Sons Inc, 2024) Abhishek Kumar; Thakur Prasad Yadav; Mohammad Abu Shaz; Nilay Krishna Mukhopadhyay
The development of alloys with substantial hydrogen storage capacities is a potential solution to the demand for hydrogen storage in a future hydrogen-based energy system. The synthesis, structural-microstructural properties, and hydrogen storage performance of a multicomponent TiZrVCrNi high-entropy melt-spun ribbon have been discussed in the present investigation. The x-ray diffraction and transmission electron microscopy investigations confirm that this as-cast and melt-spun alloy contains only a single C14-type hexagonal (a = b = 5.02 Å, c = 8.15 Å, α = β = 90°, γ = 120°) Laves phase. The room temperature pressure composition isotherms were studied with a pressure range of 0 to 40 atm. Continuing from our previous study in which we reported a hydrogen storage capacity of ~1.5 wt% in an as-cast high-entropy alloy synthesized using Arc melting, the total hydrogen storage capacity of TiZrVCrNi high-entropy melt-spun ribbons was found to be ~2 wt% in this work. This study makes the way forward for greater hydrogen storage in melt-spun ribbons. The observation of only minimal losses in storage capacity, even after 10 cycles of experiments on hydrogen absorption, shows that the reversible hydrogen storage capacity has high durability. To the best of our knowledge, these demonstrations are the first to present a study on the hydrogen storage capacity (~2 wt%) of the equiatomic TiZrVCrNi melt-spun ribbons. © 2023 John Wiley & Sons Ltd.
Improved electrocatalytic performance of delaminated-MXene and cobalt ferrite nanocomposite for hydrogen evolution in acidic medium
(Elsevier Ltd, 2025) Jyotsana Pandey; Sourabh Basu; Shalinee Dubey; Vellaichamy Ganesan; Mohammad Abu Shaz; M. Sterlin Leo Hudson
Recently, the electrochemical hydrogen evolution reaction (HER) for hydrogen generation has garnered research attention due to growing environmental concerns over fossil fuels usage. This paper discusses HER activity of cobalt ferrite and delaminated-MXene (D-MX) nanocomposites at different mass ratios. The electrochemical performance of the nanocomposites was evaluated based on their structural, microstructural, and spectroscopic features. D-MX was successfully synthesized from the MAX phase by the chemical etching route, followed by a chemical delamination process. CoFe2O4 nanoparticles (CF) were synthesized using the sol-gel auto-combustion method. It has been observed that the D-MX and CF nanocomposite with the mass ratio of 5:1 (CMX51) exhibits superior electrocatalytic behavior for HER. When compared to other mass ratios, the composite CMX51 has the lowest overpotential of 681 mV in a 0.5 M acidic solution. The CMX51 composite demonstrated a Tafel slope of 112 mV/dec for the hydrogen evolution reaction (HER), which is lower compared to that of CF. This indicates that the presence of D-MX in the nanocomposite improved the sluggish kinetic behavior of the CF nanoparticles. This may be attributed to the enhancement in ionic conductivity of CF with improved charge transfer kinetics resulting from the addition of D-MX. The Electrochemical impedance spectroscopy analysis reveals that the nanocomposite CMX51 shows improved ionic conductivity with a low charge transfer resistance. © 2025
Improved hydrogen sorption characteristics of Mg(NH2)2- 2 LiH/Li4BH4(NH2)3 using SrH2 and MgF2 auto-catalyst
(Elsevier Ltd, 2024) Vivek Shukla; Mohammad Abu Shaz; Thakur Prasad Yadav
The destabilization of the Mg(NH2)2-2LiH/Li4BH4(NH2)3 using an alkaline earth fluoride as additive such as SrF2 has been discussed and described in the present investigation. The advantage of the alkaline earth fluoride (SrF2) is that it can form two different kinds of catalysts, MgF2 and SrH2, by reacting with the MgH2 component during annealing, however, it is un-reacted when ball milled. The impact of (SrH2+MgF2) on the hydrogen storage performance of Mg(NH2)2-2LiH/Li4BH4(NH2)3 has been found to be quite effective as compared to other catalysts for hydrogen sorption. The onset desorption temperature for Mg(NH2)2–2LiH/Li4BH4(NH2)3 catalyzed by SrH2+MgF2 has been found to be 91.22 °C, whereas the temperature for uncatalyzed Mg(NH2)2–2LiH/Li4BH4(NH2)3 is 135.92 °C. The formation of auto-catalysts (SrH2+MgF2) with the in-situ formed Li4BH4(NH2)3 is much more effective on 1:2 Mg(NH2)2–LiH compared to (SrH2+MgF2)catalyzed 1:2 Mg(NH2)2–LiH. The (SrH2+MgF2)-catalyzed Mg(NH2)2- 2 LiH/Li4BH4(NH2)3 shows promising kinetics. It desorbs and absorbs 3.51 wt% and 4.21 wt% H2 in 15 min at 170 °C respectively. The cyclic stability of (SrH2+MgF2)-catalyzed Mg(NH2)2-2 LiH/Li4BH4(NH2)3 has been found to be very stable up to 10 cycles. The recovery rate was found to be 96.49 % from 10th to 1st cycle of de/re-hydrogenation. © 2024 Hydrogen Energy Publications LLC
Improved hydrogen storage characteristics of magnesium hydride using dual auto catalysts (MgF2+CsH)
(Elsevier Ltd, 2022) Rashmi Kesarwani; Vivek Shukla; M. Sterlin Leo Hudson; Mohammad Abu Shaz
This study discusses the improvement in the hydrogen sorption properties of MgH2 with dual auto-catalysts, MgF2 and CsH. The auto-catalysts are formed due to the reaction between MgH2 and CsF during the dehydrogenation reaction of MgH2. It has been observed that MgF2 and CsH not only improve MgH2's hydrogen sorption properties, also aids its positive thermodynamic tuning, which is favourable for hydrogen storage. The on-set desorption temperature of MgH2 catalysed by MgF2+CsH is 249 °C, which is 106 °C lower than that of ball-milled MgH2 without any additives measured under identical measurement conditions. The catalysts helped in improving both the de/rehydrogenation kinetics of MgH2. The MgH2 catalysed by MgF2+CsH released 4.73 wt % H2 in 15 min at 300 °C. Furthermore, its initial re-hydrogenation rate under isothermal conditon at 300 °C is 4.62 wt % H2 in 5 min. The catalysed sample exhibits negligible hydrogen storage degradation of 0.39 wt % H2 after 25 de/re-hydrogenation cycles. Using the Kissinger method, the activation energy of MgH2 catalysed by MgF2+CsH was estimated to be 98.1 ± 0.5 kJmol-1. From the Van't Hoff plot, the decomposition and formation enthalpies of MgH2 were determined to be 66.6 ± 1.1 kJmol-1 and 63.1 ± 1.2 kJmol-1, respectively. From the experimental observation, a feasible mechanism for the de/re-hydrogenation behaviour of MgH2 with MgF2+CsH is proposed. © 2022 Hydrogen Energy Publications LLC
In-situ copper and nickel incorporation in carbon aerogels for efficient hydrogen storage
(Elsevier Ltd, 2025) Pargai Neema; Ashish Bhatnagar; Satish Kumar Verma; Mohammad Abu Shaz
Transition metal-doped carbon aerogels are emerging as promising materials for hydrogen storage due to their adjustable porosity, enhanced chemical functionality, and high specific surface area. In this study, we have synthesized copper and nickel-doped carbon aerogels by in-situ doping, utilizing copper nitrate and nickel nitrate as dopants during the polymerization of resorcinol and formaldehyde using triethylamine to aid the polymerization. The synthesized pristine and chemically activated doped carbon aerogels exhibited specific surface areas of 452 m2/g and 1200 m2/g, respectively. They demonstrated hydrogen storage up to 4.93 wt% and 5.94 wt% under 22 atm pressure at liquid nitrogen temperature, respectively. The study also reveals that increasing specific surface area does not necessarily guarantee proportional increases in hydrogen uptake. Based on electron microscopy and XPS studies, it can be concluded that the balance between specific surface area, pore size distribution, and chemical functionality is critical for optimizing hydrogen storage. © 2025 Hydrogen Energy Publications LLC
Introducing 2D layered WS2 and MoS2 as an active catalyst to enhance the hydrogen storage properties of MgH2
(Elsevier Ltd, 2024) Satish Kumar Verma; Mohammad Abu Shaz; Thakur Prasad Yadav
The current work describes how 2D layered materials, such as MoS2 and WS2, might improve the de/re-hydrogenation kinetics of MgH2. In the presence of WS2 catalyst, desorption of MgH2 begins at 277 °C, with a hydrogen storage capacity of 5.95 wt%, while the onset desorption temperature of MgH2 catalyzed by MoS2 is 330 °C. In just 1.3 min at 300 °C under 13 atm hydrogen pressure, the MgH2-WS2 absorbed approximately 3.72 wt% of hydrogen, and in 20 min at 300 °C under 1 atm hydrogen pressure, it desorbed around ∼5.57 wt% of hydrogen. To ensure the cyclic stability up to 25 cycles of de/re-hydrogenation of the catalyzed MgH2, a continuously 25 cycles of dehydrogenation (under 1 atm hydrogen pressure at 300 °C) and rehydrogenation (under 13 atm hydrogen pressure at 300 °C) were carried out. As a result, MgH2-WS2 exhibits superior cyclic stability than MgH2–MoS2. In addition, with the de/re-hydrogenation kinetics, MgH2-WS2 has a lower reaction activation energy (∼117 kJ/mol) than to other catalyzed and pristine samples. Conversely, the thermodynamical parameters, specifically the change in enthalpy of MgH2, are unaffected by addition of these layered WS2 and MoS2 catalysts. © 2024 Hydrogen Energy Publications LLC
Low Dimensional Nanomaterials for Hydrogen Storage
(Springer Science and Business Media Deutschland GmbH, 2025) Yogesh Kumar Yadav; Abhishek Kumar; Mohammad Abu Shaz; Thakur Prasad Yadav
Economic expansion and population growth are the main causes of the growing demand for energy on a worldwide scale. Nowadays, fossil fuels, which are limited and non-renewable, provide 90% of the energy used worldwide. Furthermore, the main cause of greenhouse gas emissions, which have detrimental effects on the environment and human health, is the burning of fossil fuels. Because of this, switching to clean alternative energy sources is crucial. Because hydrogen fuel is sustainable, non-toxic, and emits no pollutants, it has drawn attention from all over the world. Hydrogen has an energy density of 142 MJ/kg, which is more than any other element and almost three times that of fossil fuels. In contrast to the damaging and depleting fossil fuels, hydrogen is plentiful and can be generated responsibly from water and other renewable resources. Effective hydrogen storage is still a significant obstacle, though. Storage procedures are made more difficult by its low gravimetric density (0.08988 g/L). Although hydrogen can be kept as a gas, liquid, or solid, solid-state storage is the most effective and safest option. This technique enables high-capacity storage at low pressure and close to room temperature. While materials such as carbon nanotubes and metal–organic frameworks store hydrogen by surface adsorption, metal hydrides absorb it internally. Recent developments in metal hydrides based on high-entropy alloys, which may be synthesized a variety of ways, exhibit encouraging potential for use in hydrogen production and storage. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.
Mechanistic understanding of the superior catalytic effect of Al65Cu20Fe15 quasicrystal on de/re-hydrogenation of NaAlH4
(Elsevier Ltd, 2023) Satish Kumar Verma; Ashish Bhatnagar; Mohammad Abu Shaz; Thakur Prasad Yadav
The complex hydride NaAlH4 remains the archetype hydrogen storage system. In this paper, we have explored the catalytic action of Al65Cu20Fe15 quasicrystal (QC) on the de/re-hydrogenation study of NaAlH4. The leached ball-milled Al65Cu20Fe15 (LBMACF) catalyzed NaAlH4 sample has shown a lower hydrogen desorption temperature (140 °C) than other catalyzed and uncatalyzed NaAlH4 samples. NaAlH4-LBMACF rapidly absorbed ∼3.20 wt% of hydrogen within 1 min and absorbed maximum capacity (∼4.68 wt%) in 15 min, while NaAlH4-LACF, NaAlH4-BMACF, NaAlH4-ACF, and pristine NaAlH4 absorbed only 0.50 wt%, 1.38 wt%, 1.10 wt%, and 0.70 wt% in 1 min at 130 °C under 100 atm hydrogen pressure. NaAlH4-LBMACF has desorbed ∼4.22 wt% of hydrogen within 15 min, while the same amount of hydrogen desorbed by NaAlH4-LACF takes 45 min at 130 °C under 1 atm hydrogen pressure. NaAlH4-LBMACF shows reversibility up to 25 cycles with minimum degradation of hydrogen storage capacity of ∼0.06 wt% during de/re-hydrogenation. The catalytic mechanism and catalytic effect of Al–Cu–Fe on the NaAlH4 have been discussed using structural, microstructural analysis, in-situ nuclear magnetic resonance (NMR) spectroscopy, in-situ Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). © 2022 Hydrogen Energy Publications LLC
Nanocrystallization and structural correlation in quasicrystalline and crystalline phases during mechanical milling
(2009) Radhey Shyam Tiwari; Thakur Prasad Yadav; Nilay K. Mukhopadhyay; Mohammad Abu Shaz; Onkar Nath Srivastava
The main objective of the proposed work is to investigate the formation of nanoquasicrystalline and related nanocrystalline phases in Al - Cu - Fe system during mechanical milling at the initial stage of milling. The mechanical milling of a quasicrystalline Al65Cu20Fe15 alloy was performed in a high-energy ball mill (Szegvari attritor) by varying milling time from 2.5 min to 60 min under liquid hexane medium at the speed of 400 rpm with a ball to powder ratio of 40:1. X-ray diffraction was carried out for evaluating the lattice strain, lattice parameters and crystallite sizes of the milled sample. It was found that the evolution of monoclinic Al 13Fe4 phase from Al65Cu20Fe 15 quasicrystalline phase occurred after 2.5 min of milling, which was further confirmed by transmission electron microscopy. After 5 min of ball milling nano size disordered B2 phase (bcc, a = 0.29 nm) was also found. The systematic analysis of the XRD patterns for evolving lattice parameter, sequential strain suggests that the lattice strain during milling has been quite considerable. © by Oldenbourg Wissenschaftsverlag.
Notable catalytic activity of Al–Cu–Fe–Ni–Cr high entropy alloy nanoparticles for hydrogen sorption in MgH2
(Elsevier Ltd, 2025) Yogesh Kumar Yadav; Mohammad Abu Shaz; Thakur Prasad Yadav
Magnesium hydride (MgH2) is a promising material for hydrogen storage because of its abundance and beneficial properties, such as high storage capacity and cost-effectiveness under mild conditions. Despite of these benefits, MgH2 unfavorable thermodynamics and kinetics make it difficult to use in real applications. In this work, the hydrogen storage properties of MgH2 have been improved using Al–Cu–Fe–Ni–Cr high entropy alloy (HEA) based catalysts, which has been synthesized via mechanical alloying. The experimental findings show that the beginning desorption temperature of MgH2 significantly lowered from 425 °C to 180 °C by adding 5 wt. % Al–Cu–Fe–Ni–Cr HEA in MgH2. Moreover, the catalyst shows enhanced kinetics, attaining 7.3 wt. % hydrogen absorption in 3 min at 320 °C with 15 atm hydrogen pressure, and ∼5 wt. % desorption in 6 min at 320 °C. These findings emphasize how significantly lower its desorption temperature is than those of other well-known catalysts. Over a span of 25 cycles, MgH2 catalyzed by Al–Cu–Fe–Ni–Cr HEA exhibits remarkable cyclic stability with negligible fluctuations (∼0.05 wt. %). After a thorough characterization of the materials, a workable catalytic mechanism for HEA was proposed considering the results. © 2025 Hydrogen Energy Publications LLC
Notable hydrogen storage properties in nanocrystalline Al–Cr–Cu–Fe–Ni high entropy alloy
(University of Science and Technology Beijing, 2025) Yogesh Kumar Yadav; Mohammad Abu Shaz; Thakur Prasad Yadav
The hydrogen storage mechanism of a single-phase nanocrystalline mechanically alloyed Al–Cr–Cu–Fe–Ni high-entropy alloy (HEA) was investigated in this study. The alloys were synthesized from the elemental powders using high-energy attritor ball mill with hexane as the process control agent. The material obtained after 40 h of milling was nanocrystalline and exhibited body-centered cubic (BCC) phase with a lattice parameter of 0.289 nm. The nanocrystalline Al–Cr–Cu–Fe–Ni HEA demonstrated remarkable hydrogen storage capacity at 300°C and 50 atm hydrogen pressure, absorbing 2.1wt% of hydrogen within 3 min and desorbing approximately 1.6wt% of hydrogen in 6 min. These rapid absorption and desorption processes highlighted the efficiency of the alloy for hydrogen uptake and release. Additionally, the alloy exhibited good cyclic stability, with a loss of only 0.2wt% of its hydrogen capacity across 25 cycles. The exceptional cycle stability and rapid kinetics of hydrogen storage and release make the nanocrystalline Al–Cr–Cu–Fe–Ni HEA a viable choice for hydrogen storage applications. © University of Science and Technology Beijing 2025.