Enhanced hydrogen purification by graphene - Poly(Dimethyl siloxane) membrane

In this study, a nanocomposite graphene oxide (GO) incorporated poly (dimethyl siloxane) (PDMS) membrane was produced and used for the purification of hydrogen (H₂₎ by separating the (CO₂). The produced membrane was characterized and the single-gas permeability test was performed. Effects of GO addition, trans-membrane pressure and membrane thickness on the gas separation performance of membrane were evaluated as a function of permeability and CO₂/H₂ selectivity. GO addition increased the CO₂/H₂ selectivity and H₂ purification performance. The highest CO2 permeability of 3670 Barrer and CO₂/H₂ selectivity of 11.7 were obtained when the GO loading was 0.5 wt% when the trans-membrane pressure was 0.2 Mpa.     

Active block copolymer layer on carboxyl-functionalized PET film for hydrogen separation

To rationalize the energy requirements and environmental complications of the world, supply of pure hydrogen is the most promising as well best possible approach of such issues. Purified hydrogen gas is the necessity factor for the hydrogen-based economy. Hydrogen perm-selective membrane plays a crucial role for producing a large amount of hydrogen. Palladium is one of the best materials because of its excellent affinity to absorb hydrogen. In present work, our aim to improve selectivity as well permeability of the H₂ gas compare to N₂ and CO₂ gases of the block copolymer coated functionalized porous PET membrane. Porous polyethylene terephthalate (PET) membranes having pore size 0.2 μm, functionalized with a carboxyl group. The supramolecular assembly was prepared from PS (35500)-b- P4VP (4400) and 2-(4- Hydroxyphenylazo) benzoic acid (HABA) in 1, 4-dioxane. Chemically synthesized palladium nanoparticles were deposited on carboxylated block copolymer (BC) coated porous PET membrane. It is an appropriate way to use H₂ sensitive materials with block copolymer coated functionalized membranes to enhance the selectivity of H₂. It has been found that such membranes gain better permeability and selectivity towards H₂ as compared with N₂ and CO₂. Increment with the dipping time of these membranes in the palladium nanoparticle solution, permeability as well selectivity of H₂ over N₂, CO₂ increases as the more attachment of Palladium nanoparticles. A fine active layer of block copolymer on the carboxyl functionalized PET membrane play a crucial role for hydrogen based gas separation. The magnitude of the permeability of such membranes for different gases shows dependency on the pore size of the upper layer (BC coated) of the membrane in addition to the molecule size of the permeating gas. Block copolymer coating of the membranes established an effective responsibility for the selectivity of H₂ over CO₂ gas as well over N₂ gas.     

PVDF/ionic liquid polymer blends with superior separation performance for removing CO2 from hydrogen and flue gas

We have demonstrated, for the first time, a polymer blend comprising poly(vinylidene fluoride) (PVDF) and a room-temperature ionic liquid (RTIL) that shows a high CO₂ permeability of 1778 Barrer with CO₂/H₂ and CO₂/N₂ selectivity of 12.9 and 41.1, respectively. The low viscosity RTIL, 1-ethyl-3-methylimidazolium tetracyanoborate ([emim][B(CN)₄]) possesses a high CO₂ solubility, and plays a significant role in CO₂ separation, whereas PVDF provides the mechanical strength to the blend membranes. A series of PVDF/[emim][B(CN)₄] polymer blends with different compositions were tested for their gas separation performance involving H₂, N₂ and CO₂ in both pure gas and mixed gas conditions. Both optical observation and Maxwell predictions confirm the heterogeneous nature of the PVDF/[emim][B(CN)₄] system. However, compared to miscible ionic liquid based blends, where molecular level interactions may restrain chain flexibility and reduce gas permeability, heterogeneous PVDF/RTIL blend systems show far superior gas transport properties. Most of these blend membranes outperform most reported materials and their gas transport and separation capabilities fall within the attractive region bound by the “2008 Robeson Upper Limit” for CO₂/H₂ and CO₂/N₂ gas pairs, and are also very stable at trans-membrane pressure up to 5 atm. Therefore, they are potential materials for H₂ purification and CO₂ capture from hydrogen production and flue gas.     

Thermally rearranged (TR) HAB-6FDA nanocomposite membranes for hydrogen separation

Thermally rearranged (TR) polymers exhibited a good balance of high permeability and high selectivity. For this purpose HAB-6FDA polyimide was synthesized from 3,3 dihydroxy-4,4-diamino-biphenyl (HAB) and 2,2-bis-(3,4-dicarboxyphenyl) hexafluoro propane dianhydride (6FDA) by chemical imidization. Initially, the sample was modified from pure polymer to silica nanofiller doped polymer membrane. Further the modification was done by thermal rearrangement reaction at 350 °C temperature. This modification causes a mass loss in polymer structure and therefore enhances the fractional free volume (FFV). The gases used for the permeation test were H₂, CO₂, N₂ and CH₄. Selectivity was calculated for H₂/CO₂, H₂/N₂ and H₂/CH₄ gas pairs and plotted in the Robeson's 2008 upper bound and compared with reported data. The transport properties of these gases have been compared with the unmodified membrane. Permeability of all the gases has increased to that of unmodified polymer membrane. Thermally rearranged polymer nanocomposite exhibits higher gas permeability than that of silica doped and pure polymer. Also the selectivity for H₂/CO₂ and H₂/N₂ gas pairs exceeds towards Robeson's upper bound limit. It crosses this limit dramatically for H₂/CH₄ gas pair. Polymer nanocomposite can be utilized to obtain high purity hydrogen gas for refinery and petrochemical applications.     

Effect of UV irradiation on PC membrane and use of Pd nanoparticles with/without PVP for H2 selectivity enhancement over CO2 and N2 gases

The hydrogen-based economy is one of the possible approaches toward to eliminate the problem of global warming, which are increases because of the gathering of greenhouse gases. Palladium (Pd) is well-known material having a strong affinity to the hydrogen absorbing property and thus appropriate material to embed in the membrane for the improvement of selective permeation of hydrogen gas. In present work, we have functionalized polycarbonate (PC) membranes with the help of UV irradiation to embed the Pd nanoparticles in pores as well as on the surface of the PC membrane. Use of Pd Nanoparticles is helpful to enhance the H₂ selectivity over other gases (CO₂, N_2, etc.). Also, the UV based modification of membrane increases the attachment of Pd Nanoparticles. Further to enhance the Pd nanoparticles attachment, we used PVP binder with Pd nanoparticles solution. Gas permeability measurements of functionalized PC membranes have been carried out, and better selectivity of hydrogen has been found in the functionalized and Pd nanoparticle binded membrane. PC membrane with 48 h UV irradiated and Pd NPs with PVP have been found to have maximum selectivity and permeability for H₂ gas. All the samples being characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy and UV–Vis spectroscopy for their morphological and structural investigation.     

High performance ZIF-8/PBI nano-composite membranes for high temperature hydrogen separation consisting of carbon monoxide and water vapor

Two types of advanced nano-composite materials have been formed by incorporating as-synthesized wet-state zeolitic imidazolate frameworks-8 (ZIF-8) nano-particles into a polybenzimidazole (PBI) polymer. The loadings of ZIF-8 particles in the two membranes (i.e., 30/70 (w/w) ZIF-8/PBI and 60/40 (w/w) ZIF-8/PBI) are 38.2 vol % and 63.6 vol %, respectively. Due to different ZIF-8 loadings, variations in particle dispersion, membrane morphology and gas separation properties are observed. Gas permeation results suggest that intercalation occurs when the ZIF-8 loading reaches 63.6 vol %. The incorporation of ZIF-8 particles significantly enhances both solubility and diffusion coefficients but the enhancement in diffusion coefficient is much greater. Mixed gas tests for H₂/CO₂ separation were conducted from 35 to 230 °C, and both membranes exhibit remarkably high H₂ permeability and H₂/CO₂ selectivity. The 30/70 (w/w) ZIF-8/PBI membrane has an H₂/CO₂ selectivity of 26.3 with an H₂ permeability of 470.5 Barrer, while the 60/40 (w/w) ZIF-8/PBI membrane has an H₂/CO₂ selectivity of 12.3 with an H₂ permeability of 2014.8 Barrer. Mixed gas data show that the presence of CO or water vapor impurity in the feed gas stream does not significantly influence the membrane performance at 230 °C. Thus, the newly developed H₂-selective membranes may have bright prospects for hydrogen purification and CO₂ capture in realistic industrial applications such as syngas processing, integrated gasification combined cycle (IGCC) power plant and hydrogen recovery.     

Selective deposition of Pd nanoparticles in porous PET membrane for hydrogen separation

Hydrogen purification based on Pd deposition in porous polymeric membranes show promising results for hydrogen permeability and selectivity. It is due to high absorption property of Pd nanoparticles. In this work, gas permeability of carboxylic group functionalized Polyethylene terephthalate (PET) membranes with different time of functionalization have been examined. It has been found that PET membrane having more –COOH group shows higher selectivity for Hydrogen (H₂). Further to improve the selectivity, these carboxylated PET membranes dipped in Pd nanoparticles solution for 6 h and found more selective for H₂ in comparison to Carbon dioxide (CO₂) and Nitrogen (N₂). As the carboxylation increases selectivity of H₂ improves drastically in the beginning and nearly get saturated after 24 h. Similar trend has been observed for these membranes after Pd nanoparticles deposition. Fourier transform infrared spectroscopy (FTIR) spectra of these membranes revealed that intensity of peaks related to –COOH group at 2968 cm^?1 & 1716 cm^?1 increases with functionalization time. Field Emission Scanning Electron Microscopy (FESEM) was used to study the surface morphology of membranes.     

CO2-selective membranes for hydrogen purification and the effect of carbon monoxide (CO) on its gas separation performance

Industrial hydrogen production may prefer CO₂-selective membranes because high-pressure H₂ can therefore be produced without additional recompression. In this study, high performance CO₂-selective membranes are fabricated by modifying a polymer–silica hybrid matrix (PSHM) with a low molecular weight poly(ethylene glycol) dimethyl ether (PEGDME). The liquid state of PEGDME and its unique end groups eliminate the crystallization tendency of poly(ethylene glycol) (PEG). The methyl end groups in PEGDME hinder hydrogen bonding between the polymer chains and significantly enhance the gas diffusivity. In pure gas tests, the membrane containing 50 wt% additive shows CO₂ gas permeability and CO₂/H₂ selectivity of 1637 Barrers and 13 at 35 °C, respectively. In order to explore the effect of real industrial conditions, the gas separation performance of the newly developed membranes has been studied extensively using binary (CO₂/H₂) and ternary gas mixtures (CO₂/H₂/carbon monoxide (CO)). Compared to pure gas performance, the second component (H₂) in the binary mixed gas test reduces the CO₂ permeability. The presence of CO in the feed gas stream decreases both CO₂ and H₂ permeability as well as CO₂/H₂ selectivity as it reduces the concentration of CO₂ molecules in the polymer matrix. The mixed gas results affirm the promising applications of the newly developed membranes for H₂ purification.     

Developing cross-linked poly(ethylene oxide) membrane by the novel reaction system for H2 purification

In this study, a ‘green” method has been discovered by utilizing the amino functional poly(ethylene oxide) (PEO) and epoxy functional PEO with low molecular weights to synthesis cross-linked membranes for enhancing H₂ purification and CO₂ capture performance by retarding the crystallinity of semi-crystalline polymer of PEO. The cross-linking reaction can happen simply by mixing two materials without using any solvent. The reaction has been characterized by Fourier transform infrared-attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), solid-state ¹³C nuclear magnetic resonance (NMR) and the gel content test. Furthermore, X-ray diffraction (XRD) and differential scanning calorimeter (DSC) confirm the amorphous structure of cross-linked PEO membranes, which should benefit the gas transport. The gas transport properties and the plasticizing phenomenon of CO₂ have been examined in detail. Interestingly, the investigation on CO₂ plasticization phenomenon reveals that the cross-linked PEO membrane should be plasticized immediately after the pressure load. The pressure dependence of CO₂ permeability in the pressure range from 0.25 atm to 30 atm can be separated into two stages based on the permeability increment although the CO₂ permeability continuously increases with the loading pressure. The gas transport results illustrate that CO₂ has much larger permeability than that of any tested gas (including H₂, N₂ and CH₄) attributing to the CO₂-philic characteristic of ethylene oxide (EO) groups in the cross-linked PEO membrane. The good permeability and selectivity make the developed PEO membrane promising for H₂ purification and CO₂ capture applications.     

Computational prediction of experimentally possible g-C3N3 monolayer as hydrogen purification membrane

Membrane technology has been used for hydrogen purification. In this work, two-dimensional g-C₃N₃ monolayer was proposed as an effective hydrogen separation membrane on basis of density functional theory computations. The structure of g-C₃N₃ monolayer was optimized first, and the computed phonon dispersion confirmed its stability and supported the experimental feasibility. The permeability of H₂ and impurity gases, including CO, N₂ and CH₄, was investigated. Compared with H₂, it is more difficult for the impurity gases to penetrate through g-C₃N₃ monolayer. The high selectivity of H₂ vs. CO, N₂, and CH₄ ensures a superior capability to conventional carbon and silica membranes. With high H₂ permeability and selectivity, g-C₃N₃ monolayer is a potential H₂ purification membrane.     

GNs/MOF-based mixed matrix membranes for gas separations

NU-1000 and graphene nanosheet (GNs) with different loadings have been used as fillers to prepare mixed matrix membranes (MMMs) with polyethersulfone (PES). The high performance of the MMMs has been successfully fabricated for the evaluation of gas separation at 1 bar and various temperatures (20, 40, 60 °C). The successful fabrication of the MMMs were confirmed by using SEM, FTIR, AFM, and XRD. The crystalline nature of GNs and NU-1000 in the MMMs are evidenced by XRD, which confirms the successful fabrication of the MMMs. In addition, the thermal stability of the MMMs was enhanced with the increase of the GNs. Separation performance of H₂ was superior to CO₂, N₂ and CH₄ separation on the MMMs which is a critical for producing energy. The best gas separation results in terms of both permeability and selectivity were obtained with 0.03% GNs and 10% NU-1000. PG3N membrane presented maximum H₂/CO₂, H₂/N₂ and H₂/CH₄ selectivity of 5, 4.2, 3.3 at 20 C, respectively. With an increase in temperature, the permeability increased, while the selectivity of all the MMMs decreased. The MMMs exhibited excellent gas separation capability, which offers unique opportunities for potential large-scale practical applications.     

Palladium nanoparticle binding in functionalized track etched PET membrane for hydrogen gas separation

In this work, track-etched poly (ethylene terephthalate) (PET) membranes having different pore sizes were functionalized by the carboxylic groups and the amino groups. Palladium (Pd) nanoparticles of average diameter 5 nm were synthesized chemically and deposited onto pore walls as well as on the surface of these pristine and functionalized membranes. Effect of Pd nanoparticles binding on these membranes were explored and aminated membrane were found to bind more Pd nanoparticles due to its affinity. The morphology of these composite membranes is characterized by Scanning Electron Microscope (SEM) for confirmation of Pd nanoparticle deposition on pore wall as well as on the surface. Gas permeability of functionalized and non-functionalized membranes for hydrogen and carbon dioxide has been examined. From the gas permeability data of hydrogen (H₂) and carbon dioxide (CO₂) gases, it was observed that these membranes have higher permeability for H₂ as compared with CO₂. Due to absorption of hydrogen by Pd nanoparticles selectivity of H₂ over CO₂ was found higher as compared to without Pd embedded membranes. Such type of membranes can be used to develop hydrogen selective nanofilters for purification/separation technology.     

Molecular-level mixed matrix membranes comprising Pebax and POSS for hydrogen purification via preferential CO2 removal

The molecular-level mixed matrix membranes (MMMs) comprising Pebax^® and POSS have been developed by tuning the membrane preparation process in this work. They exhibit a simultaneous enhancement in CO₂ permeability and CO₂/H₂ selectivity by optimizing the POSS content at extremely low loadings. This is mainly attributed to the large cavity of POSS itself and its effect on the segmental-level polymeric chain packing. More interestingly, the Pebax^®/POSS MMMs reveal a much higher separation performance in the mixed gas test than that in the pure gas test. The highest CO₂/H₂ selectivity reaches 52.3 accompanied by CO₂ permeability of 136 Barrer at 8 atm and 35 °C. This is due to the CO₂-induced plasticization that improves the free volume and polymer chain mobility, hence benefiting the interaction between the polymer matrix and penetrant CO₂. These features may ensure the superiority of Pebax^®/POSS molecular-level MMMs as CO₂-selective membranes in the industrial application of hydrogen purification.     

New PEEK-WC and PLA membranes for H2 separation

The potentialities of PEEK-WC (thermally treated at 120 °C) and PLA polymers have been studied in the field of membrane technology applied to H₂ separation/purification. In particular, for low/medium temperature operation (80 °C), PEEK-WC membranes (66 μm thick) showed good results in terms of H₂/CH₄ separation, showing an ideal selectivity value higher than 40. Meanwhile, we observed interesting selectivity also for H₂/N₂ and H₂/CO₂ separation, reaching values of 24 and 20, respectively. As expected, for PEEK-WC thermally treated membranes, the H₂ permeating flux increased from 25 to 80 °C and by increasing the transmembrane pressure. Furthermore, H₂ permeability at 80 °C was around 20 barrer. Concerning PLA membranes (26 μm thick), it is worth of noting that this polymer was pioneeristically used in this work as membrane application, showing great results in terms of H₂/CO₂ separation. Indeed, we overcame the Robeson's upper-bound (2008), achieving an ideal selectivity H₂/CO₂ around 25 with an H₂ permeability of 25 barrer. Further advantage due to the utilization of PLA membranes was related to the temperature operations set at ambient conditions, constituting a valuable and cost-effective solution for H₂/CO₂ separation processes via polymeric membrane technology.     

Hydrogen permeation through a Pd-based membrane and RWGS conversion in H2/CO2, H2/N2/CO2 and H2/H2O/CO2 mixtures

This study investigated the effect of gases such as CO₂, N₂, H₂O on hydrogen permeation through a Pd-based membrane −0.012 m² – in a bench-scale reactor. Different mixtures were chosen of H₂/CO₂, H₂/N₂/CO₂ and H₂/H₂O/CO₂ at temperatures of 593–723 K and a hydrogen partial pressure of 150 kPa. Operating conditions were determined to minimize H₂ loss due to the reverse water gas shift (RWGS) reaction. It was found that the feed flow rate had an important effect on hydrogen recovery (HR). Furthermore, an identification of the inhibition factors to permeability was determined. Additionally, under the selected conditions, the maximum hydrogen permeation was determined in pure H₂ and the H₂/CO₂ mixtures. The best operating conditions to separate hydrogen from the mixtures were identified.     

Evaluation of two gas membrane modules for fermentative hydrogen separation

The ability of (dimethyl siloxane) (PDMS) and SAPO 34 membrane modules to separate a H₂/CO₂ gas mixture was investigated in a continuous permeation system in order to decide if they were suitable to be coupled to a biological hydrogen production process. Permeation studies were carried out at relatively low feed pressures ranging from 110 to 180 kPa. The separation ability of SAPO 34 membrane module appeared to be overestimated since the effect concentration polarization phenomena was not taken into consideration in the permeation parameter estimation. On the other hand, the PDMS membrane was the most suitable to separate the binary gas mixture. This membrane reached a maximum CO₂/H₂ separation selectivity of 6.1 at 120 kPa of feed pressure. The pressure dependence of CO₂ and H₂ permeability was not considerable and only an apparent slight decrease was observed for CO₂ and H₂. The mean values of permeability coefficients for CO₂ and H₂ were 3285 ± 160 and 569 ± 65 Barrer, respectively. The operational feed pressure found to be more adequate to operate initially the PDMS membrane module coupled to the fermentation system was 180 kPa, at 296 K. In these conditions it was possible to achieve an acceptable CO₂/H₂ separation selectivity of 5.8 and a sufficient recovery of the CO₂ in the permeate stream.     

Effect of mesoporous silica modification on the structure of hybrid carbon membrane for hydrogen separation

An SBA-15/carbon molecular sieve (CMS) composite membrane, using polyetherimide as a precursor and mesoporous silica as filler, was fabricated for hydrogen separation. The effect of mesoporous SBA-15 on the gas transport properties of the composite membrane was evaluated. The permeability and selectivity coefficients of H₂, CO₂, O₂, N₂, and CH₄ were estimated for the pure CMS and SBA-15/CMS composite membranes at a feed pressure of 2-7 atm for 30 °C. The SBA-15/CMS composite membrane had a gas permeability higher than that of the pure CMS membrane, whereas its selectivity was the same. The permeability was found to be independent of pressure; this indicates that the gases are transported through the membrane by a molecular sieve mechanism. The membranes appeared to have a more microporous structure when the mesoporous silica SBA-15 was incorporated. These results concur with the hypothesis that SBA-15 improves gas diffusivity by increasing pore volume.     

Silica-zirconia membrane supported on modified alumina for hydrogen production in steam methane reforming unit

A hydrogen-selective and hydrothermally stable membrane composed of silica-zirconia layer deposited on a modified alumina sub layer was successfully prepared. The composite membrane was used for hydrogen purification from synthesis gas in steam methane reforming process. Silica-zirconia layer was synthesized using the CVD method at 923K and atmospheric pressure while the alumina base layer was prepared via sol-gel procedure. DLS, XRD, SEM/EDX, and BET characterization techniques were used to prove that γ-alumina base and silica-zirconia layer are fabricated successfully. Using the composite membrane, hydrogen selectivity toward other gases has improved significantly. Moreover, H₂/CH₄, H₂/CO, and H₂/CO₂ selectivity have been increased from 700, 350 and 70 in 5 h CVD synthesized membrane to 1600, 750 and 570 for 12 h CVD synthesized membrane respectively. The synthesized Silica-Zirconia membrane successfully altered gases permeability tendency order from H₂ > CH₄ > CO₂ > CO to H₂ > CO₂ > CO > CH₄ which leads to better separation of the product from methane feed. Finally, hydrothermal stability test demonstrated that permeability loss in silica-zirconia CVD coated membrane for H₂ is 45.7% after 48 h, while for silica CVD coated on the modified alumina approaches 92.5%.     

Co-based zeolitic imidazolate framework ZIF-9 membranes prepared on α-Al2O3 tubes through covalent modification for hydrogen separation

Hydrogen has been regarded as the most promising clean and renewable energy. Beside the production of the hydrogen, the separation of hydrogen is also an import issue before it can be used in fuel cells. Membrane-based separation technologies have gained considerable attentions due to its high efficiency and low energy consumption. Zeolite imidazolate framework (ZIF) membranes have drawn intense interest due to their zeolite-like properties such as permanent porosity, uniform pore size and exceptional thermal and chemical stability. It is rather challenged to prepare well-intergrown Co-based zeolitic imidazolate frameworks (ZIFs) membranes on porous α-Al₂O₃ tubes since Co-based ZIFs prefer to form crystals in the synthesis solution rather than grow as membrane layer on the support surface. In this work, we report the preparation of high-quality ZIF-9 membrane with high H₂/CO₂ selectivity and excellent thermal stability by using 3-aminopropyltriethoxysilane (APTES) as a covalent linker to modify the α-Al₂O₃ tube. Due to the formation of covalent bonds between APTES and ZIF-9, ZIF-9 nutrients are bound to the support surface, thus promoting the growth of dense and phase-pure ZIF-9 membrane with a thin thickness of about 4.0 μm. The gas separation performances of the ZIF-9 membrane were evaluated by single gas permeation and mixture gas separation of H₂/CO₂, H₂/N₂ and H₂/CH₄, respectively. The mixture separation factors of H₂/CO₂, H₂/CH₄, and H₂/N₂ of the ZIF-9 membrane are 21.5, 8.2 and 14.7, respectively, which by far exceeds corresponding Knudsen coefficients. Moreover, the as-prepared ZIF-9 membrane exhibits excellent stability at a relatively broad range of operating temperature, which is beneficial for the industrial application of hydrogen separation or further membrane reactor.     

Selective and efficient hydrogen separation of Pd–Au–Ag ternary alloy membrane

The widespread demand for clean energy stimulates great interest to hydrogen energy with high energy density and conversion efficiency. Separation technologies by membranes are increasingly applied for hydrogen separation because of its excellent performance and low consumption. In this work, density functional theory simulations is used to study hydrogen separation of Pd–Au–Ag membrane, and the performance of Pd–Au alloy is also compared and discussed. The results indicate that Pd–Au alloy shows superior selectivity to H₂ gas over CO, N₂, CH₄, CO₂ and H₂S gases, which is in line with experimental results. In particular, the separation selectivity of Pd–Au–Ag to H₂ is significantly greater than those for Pd–Au alloy and several currently reported materials. Moreover, the permeability of H₂ in Pd–Au–Ag exceeds the limits for industrial production at deferent temperatures. Our calculations demonstrate that Pd–Au–Ag alloy present excellent performance as a promising membrane for hydrogen separation.