Hydrogen

Improvements in quality of life, new technologies and population growth have significantly increased energy consumption in Brazil and around the world. The Paris Agreement aims to limit global warming and promote sustainable development, making green hydrogen a fundamental option for industrial decarbonization. Green hydrogen, produced through the electrolysis of water using renewable energy, is gaining traction as a solution to reducing carbon emissions, with the global hydrogen market expected to grow substantially. This study applies the ${\rho }_{DCCA}$ method to evaluate the cross-correlation between the green hydrogen market and various financial assets, including the URTH ETF, Bitcoin, oil futures, and commodities, revealing some strong positive correlations. It highlights the interconnection of the green hydrogen market with developed financial markets and digital currencies. The cross-correlation between the green hydrogen market and the index representing global financial markets presented a value close to 0.7 for small and large time scales, indicating a strong cross-correlation. The green hydrogen market and Bitcoin also presented a cross-correlation value of 0.4. This study provides valuable information for investors and policymakers, especially those concerned with achieving sustainability goals and environmental-social governance compliance and seeking green assets to protect and diversify various traditional investments. Full article

Hydrogen is considered a key energy carrier for which interest has grown over recent years. Chlor-alkali plants in the United States (U.S.) can potentially recover and supply the by-product hydrogen at scale. However, there is a scarcity of standard analysis for energy use and emissions associated with products from chlor-alkali plants owing to lack of data and variations in chlor-alkali plant technology and operation. A rigorous life cycle analysis (LCA) is needed to quantify the emissions of by-product hydrogen and other products from chlor-alkali plants. In this study, we performed well-to-gate (WTG) emissions analysis of chlor-alkali products based on U.S. plant operating data gathered from the U.S. Environmental Protection Agency’s (EPA’s) Chemical Data Reporting database, the U.S. Energy Information Administration survey EIA-923 form, and the EPA’s Greenhouse Gas Reporting Program. We performed process-level mass allocation to allocate energy use and emissions to the chlor-alkali products. This study shows that the by-product hydrogen has WTG CO₂ emissions of 1.3–1.9 kgCO₂/kg H₂ for plants without combined heat and power (non-CHP) and 1.5–2.4 kgCO₂/kg H₂ for plants with combined heat and power (CHP). Furthermore, we identified that electricity upstream emissions are the key driver affecting the emissions of by-product hydrogen from non-CHP plants, while CHP emissions can be reduced by electricity export to grids with higher carbon intensity (CI). Finally, the study shows that chlor-alkali plants in the U.S. can potentially meet up to 320 kilotons of hydrogen demand (approximately 3% of total demand) annually. Full article

As the pursuit of greener energy solutions continues, industries worldwide are turning away from fossil fuels and exploring the development of sustainable alternatives to meet their energy requirements. As a signatory to the Paris Agreement, Australia has committed to reducing greenhouse gas emission by 43% by 2030 and reaching net-zero emissions by 2050. Australia’s domestic maritime sector should align with these targets. This paper aims to contribute to ongoing efforts to achieve these goals by examining the technical and commercial considerations involved in retrofitting conventional vessels with hydrogen power. This includes, but is not limited to, an analysis of cost, risk, and performance, and compliance with classification society rules, international codes, and Australian regulations. This study was conducted using a small domestic commercial vessel as a reference to explore the feasibility of implementation of hydrogen-fuelled vessels (HFVs) across Australia. The findings indicate that Australia’s existing hydrogen infrastructure requires significant development for HFVs to meet the cost, risk, and performance benchmarks of conventional vessels. The case study identifies key determining factors for feasible hydrogen retrofitting and provides recommendations for the success criteria. Full article

Background: This study applied levelized cost of hydrogen (LCOH) and environmental cost accounting techniques to evaluate the feasibility of producing green hydrogen (GH₂) via alkaline electrolysis for use in a bus fleet in Fortaleza, Brazil. Methods: A GH₂ plant with a 3 MW wind tower was considered in this financial project. A sensitivity analysis was conducted to assess the economic viability of the project, considering the influence of production volume, the number of electrolysis kits, financing time, and other kay economic indices. Revenue was derived from the sale of by-products, including green hospital oxygen (GHO₂) and excess wind energy. A life cycle assessment (LCA) was performed to quantify material and emission flows throughout the H₂ production chain. A zero-net hydrogen price scenario was tested to evaluate the feasibility of its use in urban transportation. Results: The production of GH₂ in Brazil using alkaline electrolysis powered by wind energy proved to be economically viable for fueling a hydrogen-powered bus fleet. For production volumes ranging from 8.89 to 88.9 kg H₂/h, the sensitivity analysis revealed high economic performance, achieving a net present value (NPV) between USD 19.4 million and USD 21.8 million, a payback period of 1–4 years, an internal rate of return (IRR) of 24–90%, and a return on investment (ROI) of 300–1400%. The LCOH decreased with increased production, ranging from 56 to 25 USD/MWh. Over the project timeline, GH₂ production and use in the bus fleet reduced CO₂ emissions by 53,000–287,000 t CO₂ eq. The fuel cell bus fleet project demonstrated viability through fuel cost savings and revenue from carbon credit sales, highlighting the economic, social, and environmental sustainability of GH₂ use in urban transportation in Brazil. Full article

As the global shift toward a low-carbon economy accelerates, hydrogen is emerging as a crucial energy source. Among conventional methods for hydrogen production, steam methane reforming (SMR), commonly paired with pressure swing adsorption (PSA) for hydrogen purification, stands out due to its established infrastructure and technological maturity. This comprehensive techno-economic analysis focuses on membrane-based hydrogen production, evaluating four configurations, namely SMR, SMR with PSA, SMR with a palladium membrane, and SMR with a ceramic–carbonate membrane coupled with a carbon capture system (CCS). The life cycle cost (LCC) of each configuration was assessed by analyzing key factors, including production rate, hydrogen pricing, equipment costs, and maintenance expenses. Sensitivity analysis was also conducted to identify major cost drivers influencing the LCC, providing insights into the economic and operational feasibility of each configuration. The analysis reveals that SMR with PSA has the lowest LCC and is significantly more cost-efficient than configurations involving the palladium and ceramic–carbonate membranes. SMR with a ceramic–carbonate membrane coupled with CCS also demonstrates the most sensitive to energy variations due to its extensive infrastructure and energy requirement. Sensitivity analysis confirms that SMR with PSA consistently provides the greatest cost efficiency under varying conditions. These findings underscore the critical balance between cost efficiency and environmental considerations in adopting membrane-based hydrogen production technologies. Full article

With the increasing utilization of renewable energy sources, hydrogen production from complementary wind and solar (HPCWS) systems has become a part of the construction of the integrated energy system (IES). However, renewable energy generation faces uncertainty; in addition, the IES lacks model representation. To solve this problem, this study proposes a carbon day-ahead optimal dispatch model for an integrated energy system with HPCWS and establishes carbon equations for conventional power generation and natural gas. The demand-side response of the IES is considered in conjunction with the objective functions of low-carbon operation and hydrogen storage gain maximization; furthermore, constraints are established to keep the dispatch results of the equipment within reasonable limits. Secondly, the scheduling model requires a faster and more accurate solution algorithm, so an improved particle swarm algorithm is proposed to solve the minimum of the objective function, and the superior convergence speed and accuracy of the algorithm are verified. The comparison of the IES before and after the introduction of HPCWS yields the changes in carbon emission values and hydrogen production before and after the optimization for the respective seasons and scenarios. In addition, the article also discusses the effect of season on the optimization results. Full article

This study evaluates the performance and feasibility of hybrid photovoltaic–hydrogen systems integrated with 4.2 MW PV installations, focusing on the interplay between electrolyzer capacity, energy storage, and hydrogen production. Key findings reveal that downsizing electrolyzers, such as using a 1 MW unit instead of a 2 MW model, increases operational efficiency by extending nominal power usage, though it reduces total hydrogen output by approximately 50%. Meanwhile, expanding energy storage systems show diminishing returns, with added capacity offering minimal gains in hydrogen production and raising economic concerns. The system’s performance is highly weather-dependent, with daily hydrogen production ranging from 26 kg on cloudy winter days to 375 kg during sunny summer conditions. Surplus energy export to the grid peaks at 3300 kWh during periods of high solar generation but is minimal otherwise. For economic and operational viability, the system design must prioritize directing a majority of PV energy to hydrogen production while minimizing grid export, requiring a minimum of 50% PV energy allocation to the hydrogen value chain. Cost analysis estimates a Levelized Cost of Hydrogen (LCOH) as low as €6/kg with an optimized configuration of a 2 MW electrolyzer and 2 MWh battery. Although high production costs challenge economic sustainability, careful component optimization and supportive policies can enable competitive hydrogen pricing and a positive net present value (NPV) over the system’s lifetime. Full article

A multiparametric study was conducted on a hydrogen (H₂) production rig designed to process 0.25 Nm³·h⁻¹ of syngas. The rig consists of two Pd-Ag membrane permeator units and two Pd-Ag membrane reactor units for the water–gas shift (WGS) reaction, enabling a detailed and comprehensive analysis of its performance. The aim was to find the optimal conditions to maximize hydrogen production by WGS and its separation in a pure stream by varying the temperature, pressure, and steam-to-CO ratio (S/CO). Two syngas mixtures obtained from an updraft gasifier using different gasification agents (air–steam and oxy–steam) were used to investigate the effect of gas composition. The performance of the rig was investigated under nine combinations of temperature, pressure, and S/CO in the respective ranges of 300–350 °C, 2–8 bar, and 1.1–2 mol·mol⁻¹, as planned with the help of design of experiment (DOE) software. The three parameters positively affected performance, both in terms of capacity to separate a pure stream of H₂, reported as moles permeated per unit of surface area and time, and in producing new H₂ from WGS, reported as moles of H₂ produced per volume of catalyst unit and time. The highest yields were obtained using syngas from oxy–steam gasification, which had the highest H₂ concentration and was free of N₂. Full article

The activities of Pt electrocatalysts modified with a prepared silica powder (with SiO₂ contents of 3 and 7 wt%) in the oxygen reduction reaction in the temperature range from 0 °C to 50 °C were investigated by the rotating disk electrode technique to evaluate their efficiency in the process of the cold start of a proton-exchange membrane fuel cell (PEMFC). An increase in the mass activity of the Pt-SiO₂/C electrocatalyst in comparison with Pt/C was observed, which can be attributed to a more dispersed distribution of platinum particles on the support surface and a decrease in their size. The activity values of the silica-modified electrocatalysts in the oxygen reduction reaction were approximately two-fold higher at 1 °C and four-fold higher at elevated temperatures of up to 50 °C in comparison with Pt/C, which makes their application in PEMFCs at low temperatures, including in the process of cold start, a promising avenue for further investigation. Full article

Hydrogen is a pivotal energy carrier for achieving sustainability and stability, but safe and efficient geological underground hydrogen storage (UHS) is critical for its large-scale application. This study investigates the impacts of geochemical and biochemical reactions on UHS, addressing challenges that threaten storage efficiency and safety. Geochemical reactions in saline aquifers, particularly the generation of hydrogen sulfide (H2S), were analyzed using advanced compositional and geochemical modeling calibrated with experimental kinetic data. The results indicate that geochemical reactions have a minimal effect on hydrogen consumption. However, by year 10 of storage operations, H₂S levels could reach 12–13 ppm, necessitating desulfurization to maintain storage performance and safety. The study also examines the methanogenesis reaction, where microorganisms consume hydrogen and carbon dioxide to produce methane. Numerical simulations reveal that microbial activity under suitable conditions can reduce in situ hydrogen volume by up to 50%, presenting a critical hurdle to UHS feasibility. These findings highlight the necessity of conducting microbial analyses of reservoir brines during the screening phase to mitigate hydrogen losses. The novelty of this work lies in its comprehensive field-scale analysis of impurity-induced geochemical and microbial reactions and their implications for underground hydrogen storage. By integrating kinetic parameters derived from experimental data with advanced computational modeling, this study uncovers the mechanisms driving these reactions and highlights their impact on storage efficiency, and safety. By offering a detailed field-scale perspective, the findings provide a pivotal framework for advancing future hydrogen storage projects and ensuring their practical viability. Full article

Hydrogen (H2) offers a green medium for storing the excess from renewables production instead of dumping it, thus being crucial to decarbonisation efforts. Hydrogen also offers a storage medium for the grid’s cheap electricity to be used during grid peak demand or grid power cutoffs. Funded by the Scottish Government’s Emerging Energy Technologies, this paper presents the design and performance analysis of a hydrogen uninterruptible power supply (H2GEN) for Cygnas Solutions Ltd., which is intended to enable continuity of supply in the residential sector while eradicating the need for environmentally and health risky lead–acid batteries and diesel generator backup. This paper presents the design, optimal sizing and analysis of two H2Gen architectures, one powered by the grid alone and the other powered by both the grid and a renewable (PV) source. By developing a model of each architecture in the HOMER space and using residential location weather data, the home yearly load–demand profile, and the grid yearly power outages profile in the developed models, the optimal sizing of each H2Gen design was realised by minimising the costs while ensuring the H2Gen meets the home power demand during grid outages To enable HOMER to optimise its selection, the sizes, technical specifications and costs of all the market-available H2GEN components were added in the HOMER search space. Moreover, the developed models were also used in assessing the sensitivity of the simulation outputs to several changes in the modelled system design and settings. Using a residential home with frequent power outages in New Delhi, India as a case study, it was found that the optimal sizing of H2Gen Architecture 1 is comprised of a 2 kW electrolyser, a 0.2 kg type-I tank, and a 2 kW water-cooled fuel cell directly connected to the AC bus, offering an operational lifetime of 14.3 years. It was also found that the optimal sizing of Architecture 2 is comprised of a 1 kV PV utilised with the same 2 kW electrolyser, 0.2 kg type-I tank and 2 kW water-cooled fuel cell connected to the AC bus. While the second design was found to have a higher capital cost due to the added PV, it offered a more cost-effective and environmentally friendly architecture, which contributes to the ongoing energy transition. This paper further investigated the capacity expansion of each H2GEN architecture to meet higher load demands or increased grid power outages. From the analysis of the simulation results, it has been concluded that the most feasible and cost-effective H2GEN system expansion for meeting increased power demands or increased grid outages can be realised by using the developed models for optimally sizing the expanded H2Gen on a case-by-case basis because the increase in these profiles is highly time-dependent (for example, an increased load demand or increased grid outage in the morning can be met by the PV, while in the evening, it must be met by the H2GEN). Finally, this paper investigated the impact of other environmental variables, such as the temperature and relative humidity, on the H2GEN’s performance and provided further insights into increasing the overall system efficiency and cost benefit through utilising the H2GEN’s exhaust heat in the home space for heating/cooling and selling the electrolyser exhaust’s O₂ as a commodity. Full article

Positron physical-chemistry has been one important focus of scientific investigation of the last decades, however their low energy scattering by atoms and molecules still offers many questions to be answered, as the low angle scattering effects on the measured cross sections and how the degree of target polarization manifest in the comparison between theoretical and experimental results. In this work, we investigate low energy positron collisions by H₂ molecules, with particular attention to the convergence of the polarization contribution on the scattering potential. The interaction between positron and molecule was represented by a model potential conceived from the composition of a free electron gas correlation term with an asymptotic polarization potential, obtained from perturbation theory. In particular, we investigated how polarization effects beyond the second order perturbation affect the scattering observables. Our results show that the model which includes up to the quadrupole polarization contribution presents better agreement to the recent experimental data when corrected for forward scattering effects, since they were measured from a transmission beam technique. The angular distributions were also examined through the comparison between our results to the folded differential cross sections measurements available in the literature. We propose a simple correction scheme to the experimental folded differential cross sections for energies below 1 eV which then, as we argue, favorably compares to the quadrupole polarization model. Finally, the comparison between our phase shifts and scattering lengths with recent full many body ab initio results that explicitly include virtual positronium effects suggests that these are intrisically included in the adopted model correlation potential. Full article

This paper presents an innovative approach to fast frequency control in electric grids by leveraging parked fuel cell electric vehicles (FCEVs), especially heavy-duty vehicles such as trucks. Equipped with hydrogen storage tanks and fuel cells, these vehicles can be repurposed as dynamic grid-support assets while parked in designated areas. Using an external cable and inverter system, FCEVs inject power into the grid by converting DC from fuel cells into AC, to be compatible with grid requirements. This functionality addresses sudden power imbalances, providing a rapid and efficient solution for frequency stabilization. The system’s external inverter serves as a central control hub, monitoring real-time grid frequency and directing FCEVs to supply virtual inertia and primary reserves through droop control, as required. Simulation results validate that FCEVs could effectively complement thermal generators, preventing unacceptable frequency drops, load shedding, and network blackouts. A techno-economic analysis demonstrates the economic feasibility of the concept, concluding that each FCEV consumes approximately 0.3 kg of hydrogen per day, incurring a daily cost of around EUR 1.5. For an island grid with a nominal power of 100 MW, maintaining frequency stability requires a fleet of 100 FCEVs, resulting in a total daily cost of EUR 150. Compared to a grid-scale battery system offering equivalent frequency response services, the proposed solution is up to three times more cost-effective, highlighting its economic and technical potential for grid stabilization in renewable-rich, non-interconnected power systems. Full article

It is likely that blending hydrogen into natural gas grids could contribute to economy-wide decarbonization while retaining some of the benefits that natural gas networks offer energy systems. Hydrogen injection into existing natural gas infrastructure is recognised as a key solution for energy storage during periods of low electricity demand or high variable renewable energy penetration. In this scenario, natural gas networks provide an energy vector parallel to the electricity grid, offering additional energy transmission capacity and inherent storage capabilities. By incorporating green hydrogen into the NG network, it becomes feasible to (i) address the current energy crisis, (ii) reduce the carbon intensity of the gas grid, and (iii) promote sector coupling through the utilisation of various renewable energy sources. This study gives an overview of various interchangeability indicators and investigates the permissible ratios for hydrogen blending with two types of natural gas distributed in Tunisia (ANG and MNG). Additionally, it examines the impact of hydrogen injection on energy content variation and various combustion parameters. It is confirmed by the data that ANG and MNG can withstand a maximum hydrogen blend of up to 20%. The article’s conclusion emphasises the significance of evaluating infrastructure and safety standards related to Tunisia’s natural gas network and suggests more experimental testing of the findings. This research marks a critical step towards unlocking the potential of green hydrogen in Tunisia. Full article

In this work, the results of clean hydrogen production from the direct chemical reaction between aluminum–lithium compounds and distilled water under normal conditions, without additives or catalysts, are presented. The material was prepared by mechanical alloying using a high-energy Spex-type mill in an Al20Li ratio. Relatively short milling times were programmed for the preparation of AlLi phases. Through this process, two phases (AlLi and Al8.9Li1.1) were identified, which react efficiently to produce clean hydrogen. The experiments demonstrate fast and self-sustained reactions between AlLi phases and distilled water. In both the phase preparation and hydrogen generation, 100% efficiency was achieved. The hydrolysis reaction occurred quickly, and the hydrogen volume generated was 1700 mL/g of material. Under these conditions, aluminum generates 1390 mL of hydrogen, and lithium generates 310 mL/g from both AlLi phases. A single by-product (LiAl₂(OH)₇·2H₂O) was identified. According to the results and the conditions applied in this research, the hydrogen produced does not require prior purification and can therefore be used directly in fuel cells. The AlLi–water reaction is a promising process for generating hydrogen in a simple and relatively short time compared to other hydrogen production methods. In this process, no greenhouse gas emissions were produced. Full article

The cleanliness of hydrogen energy throughout its life cycle has enabled its applications in transportation and buildings. However, such scenarios often involve the storage and use of hydrogen in enclosed spaces. Ensuring the facility’s safety during hydrogen accidental leakage through rapid detection and emergency measures has been a long-standing topic. In this work, we analyze hydrogen leakage in a hydrogen bus through CFD simulation. By extracting the hydrogen diffusion time and combining it with the leakage frequency and ignition probability, we quantitatively evaluate the placement of the sensors and propose an index for detection system assessment named the average detection delay index (ADDI). A near-field detection sensor was introduced to the system, which reduced the lower ADDI limit of the detection system by up to 10 times while reducing the system cost without changing the level of performance. Full article

Innovative and sustainable solutions are increasingly necessary as concerns about fossil fuels’ environmental and economic impacts grow. Accordingly, this study aims to enhance vehicle internal combustion engine efficiency by producing oxy-hydrogen (HHO) from drain water from the vehicle air conditioning system and utilizing it as a secondary fuel. A 1600 cc Daewoo engine equipped with electronic fuel injection was employed as the test subject. Initially, the engine’s performance was evaluated using various gasoline variants, 80, 92, and 95. The 92-octane gasoline demonstrated the highest efficiency, achieving a peak power of 113 kW and torque of 190 Nm. The engine had an 11:1 compression ratio. Then, different flow rates of oxy-hydrogen, 50, 248, 397, and 480 mL/min, generated from the air conditioner drain were combined with 92 fuel. A significant improvement was observed with the increase in the flow rate of oxy-hydrogen gas to the 92 fuel. The results indicated that incorporating 480 mL/min oxy-hydrogen gas into the fuel led to an 8.7% reduction in fuel consumption, 5.5% enhancement in thermal efficiency, and 7.9% in volumetric efficiency. Greenhouse gas emissions reductions of carbon monoxide, carbon dioxide, and hydrocarbons were recorded as 18%, 9.2%, and 9%, respectively. At the same time, nitrogen oxides increased by 12.5%. Therefore, utilizing a vehicle air conditioner drain water to generate oxy-hydrogen gas fuel in conjunction with 92-octane gasoline is an efficient solution to reduce fuel consumption, enhance energy efficiency, and mitigate the adverse effects of pollution. This approach also contributes to progress towards a more sustainable future. Full article

Enhanced photo-induced electron utilization leads to efficient photocatalytic hydrogen production. The inefficient separation of photo-induced electron–hole pairs has hindered this process. This study introduces a synergistic approach using defect-rich SnS₂ and Ti₃C₂ MXene as cocatalysts in a two-step hydrothermal process to address this challenge. By integrating these materials with TiO₂ nanosheets, we create a novel composite, SnS₂/Ti₃C₂/TiO₂ (STT), that significantly boosts photocatalytic hydrogen evolution. The defect-rich SnS₂ provides abundant active sites for hydrogen generation, while Ti₃C₂ MXene facilitates photo-induced charge separation. The synergistic combination of charge carrier diffusion enhances chromophore absorption, thereby increasing the overall photocatalytic hydrogen-production rate, achieving several grams of hydrogen per hour per gram of double cocatalysts with molybdenum vacancies. Characterization techniques confirm the phase composition of the composite (STT). Compared to pristine TiO₂ and other composites, the STT composite, optimized with a 150 °C hydrothermal treatment, shows a photocatalytic H₂-production rate nearly 192 times higher than that of pure TiO₂ and 6 times higher than that of other composites. The presence of molybdenum vacancies in SnS₂ further enhances its specific activity for hydrogen evolution by suppressing carrier recombination and providing additional active sites. Moreover, Ti₃C₂ MXene and SnS₂ act as dual cocatalysts, improving electronic conductivity and electron-transfer efficiency. Our findings demonstrate the potential of combining defect-rich SnS₂ and Ti₃C₂ MXene to develop highly efficient and sustainable photocatalysts for hydrogen production. TiO₂ has been in situ grown on highly conductive Ti₃C₂ MXene, and SnS₂, rich in molybdenum vacancies, is uniformly distributed on the TiO₂/Ti₃C₂ composite through the two-step hydrothermal method. The presence of molybdenum vacancies in SnS₂ further enhances its specific activity for hydrogen evolution by suppressing carrier recombination and providing additional active sites. Moreover, Ti₃C₂ MXene and SnS₂ act as dual cocatalysts, improving electronic conductivity and electron-transfer efficiency. Our findings demonstrate the potential of combining defect-rich SnS₂ and Ti₃C₂ MXene to develop highly efficient and sustainable photocatalysts for hydrogen production. Full article

Novel multicomponent Nb–Ni–Ti–Zr–Co alloys with 20–55 at.% Nb were synthesized from metal powders by arc melting. The resulting alloys consist primarily of Nb-rich and eutectic body-centered (BCC) phases. The content of the eutectic BCC phase is highest for an equimolar composition, while the content of the Nb-rich BCC phase increases with Nb content in the alloy. The content of secondary phases is the highest for the alloy with 32 at.% Nb. According to ab initio calculations, hydrogen occupies tetrahedral interstitial sites in the Nb-rich phase and octahedral sites in the eutectic BCC phase. For different Nb concentrations, hydrogen-binding energies were calculated. An increase in the Nb-rich phase leads to softening of multicomponent alloys. The alloys with 20 and 32 at.% Nb demonstrate high hydrogen permeability (1.05 and 0.96 × 10⁻⁸ molH₂m⁻¹s⁻¹Pa^−0.5, respectively) at 400 °C, making them promising for hydrogen purification membrane application. Multicomponent alloys with a high Nb content (55 at.%) have low resistance to hydrogen embrittlement. Full article