Maximum Hydrogen Research Articles

Optimization of hydrogen ejector structure in proton exchange membrane fuel cell system under wide operating conditions

ABSTRACT Considering the characteristics of the hydrogen ejector for proton exchange membrane fuel cell system used in vehicles, with the aim of expanding the operating range, the ejector structure parameters are comprehensively analyzed and optimized. The results indicate that reducing the throat diameter can expand its operating range. When the working conditions change significantly, the convergent nozzle should be selected, the convergence length and throat length of the nozzle have little effect on the ejection performance. There are optimal suction chamber convergence length (8 mm), diffuser divergent angle (7.1°) and length (33.8 mm), nozzle exit position (−7 mm) in variable working conditions to achieve good ejection performance. Reducing the diameter and length of the mixing chamber is beneficial for expanding the operating range. Before ejector optimization, when the primary fluid mass flow rate is less than the design value, the ejection performance deteriorates sharply with the decrease of the flow rate. When the primary fluid mass flow rate is lower than 0.4 g/s, the non-optimization ejector is backflow, the maximum ejection ratio is about 1.8 and the maximum hydrogen ejection ratio is about 0.67 in the operating range. After optimization, the ejector performance is stable. Under the set operating conditions, the hydrogen ejection ratio is greater than 0.75, the maximum ejection ratio is 3.8, and the maximum hydrogen ejection ratio is 1.01.

Synergistic enhancement of hydrogen storage performance of Mg-La-Ni alloy by CeO2@C composite catalyst

An enhanced chemical blowing carburation method was successfully employed to synthesize a CeO2@C composite catalyst. The catalyst comprises highly dispersed CeO2 nanoparticles within a porous carbon matrix, demonstrating a well-developed micropore structure, an ultrahigh specific surface area, and a high density of defects. Various amounts of CeO2@C were mechanically milled with an Mg96La3Ni alloy to investigate its hydrogen storage properties. The results demonstrated that incorporating CeO2@C significantly refined the Mg-based alloy, leading to an increase in both specific surface area and the number of active sites. The addition of CeO2@C greatly enhanced the hydrogen absorption and desorption kinetics of the alloy, with the optimal amount being 5 wt % CeO2@C. At 360 °C, the alloy could absorb 78.1% of its maximum hydrogen capacity within 2 min, and release an equal amount of hydrogen within 5 min, with the desorption activation energy decreasing to 107.33 kJ/mol H2. The incorporation of CeO2@C significantly reduced the desorption activation energy of the alloy while leaving its thermodynamic performance unaffected. The CeO2 nanoparticles and carbon matrix synergistically catalyze the reactions, with the former primarily facilitating nucleation and the latter facilitating hydrogen diffusion. This study offers novel insights into the design of magnesium-based hydrogen storage materials. The enhanced hydrogen storage performance demonstrated in this work shows the potential of CeO2@C modified Mg-based alloys for practical applications in hydrogen fuel cell vehicles, portable power sources, and other hydrogen energy storage systems.

Spin-polarization and crystal structure engineering enhanced photocatalytic H2 production and photoluminescence properties in cobalt-doped CsPbBr3

In this study, the effect of Co doping in CsPbBr3 perovskite on phase transition and photocatalytic hydrogen production under a magnetic field was studied. Square CsPbBr3 nanoparticles with a dimension of 30–40 nm have been synthesized by the hot injection method. Rietveld refinement on the XRD pattern revealed the phase transition from cubic to orthorhombic after Co doping. The addition of 3%Co to CsPbBr3 resulted in a significant hydrogen production capacity of 3500 μmol/g in 4 h, with the maximum hydrogen production rate of 1042.11 μmol/g·h in the first hour, which was 1.80 times the maximum hydrogen production rate of bare CsPbBr3 (581.66 μmol/g·h). Notably, the photocatalytic H2 production of 3%Co: CsPbBr3 perovskite is significantly enhanced by applying an external magnetic field. Under the magnetic field of 2 T, the hydrogen production capacity of Co: CsPbBr3 increased to 5300 μmol/g in 4 h, with the maximum hydrogen production rate of 1828.36 μmol/g·h in the first hour, being 3.14 times the maximum hydrogen production rate of CsPbBr3 without magnetic field. The corresponding mechanism is systematically investigated by a vibrating-sample magnetometer, Electron paramagnetic resonance, UV–visible absorption, and photoluminescence spectra. The photocurrent and EIS were applied to investigate the charge-transfer kinetics of Co–CsPbBr3. The excellent photocatalytic H2 production efficiencies are because the doping of magnetic Co into highly polarized orthorhombic CsPbBr3 increased the number of spin-polarized photo-generated carriers while applying magnetic field provided spin polarization and more electron transport channels, suppressing the recombination efficiency of electrons and holes. Manipulating spin-polarized electrons in highly polarized orthorhombic photocatalytic semiconductors provides an effective strategy to boost photocatalytic H2 production efficiencies.

Annealing cracking in Zr and a Zr-alloy with low hydrogen concentration

Hydrogen embrittlement, also known as hydrogen-induced cracking, is a longstanding concern for zirconium (Zr) and its alloys. The affinity for hydrogen in zirconium results in the formation of brittle hydrides. Hydrides are conventionally thought to facilitate crack propagation, and the prevailing recommendation to hinder hydride embrittlement involves reducing the hydrogen concentration in the material and applying slow cooling to reduce thermal stresses. Here, in Zr with a maximum hydrogen concentration of 43 wppm, we show that cracks initiate unexpectedly after annealing, a step that involves slow cooling and no external stress. With a suite of high-resolution microscopy, we show that annealing cracks initiate at prismatic δ-hydrides, whose presence is unexpected. The microscopic annealing crack paths are consequently crystallographic, following the habit plane of these prismatic δ-hydrides. The commonly reported γ-hydride and δ-hydrides that develop on the basal plane are found not to initiate cracks. We rationalize that prismatic δ hydrides result from the intergranular thermal residual stresses that develop during slow cooling. This finding of uncommon annealing cracking further advances the mechanistic understanding of hydride embrittlement in zirconium and can lead to new strategies for design and fabrication of advanced zirconium alloys for harsh environments.

Hydrogen storage capacity of salt caverns and deep aquifers versus demand for hydrogen storage: A case study of Poland

Geological structures in deep aquifers and salt caverns can play an important role in large-scale hydrogen storage. However, more work needs to be done to address the hydrogen storage demand for zero-emission energy systems. Thus the aim of the article is to present the demand for hydrogen storage expressed in the number of salt caverns in bedded rock salt deposits and salt domes or the number of structures in deep aquifers. The analysis considers minimum and maximum hydrogen demand cases depending on future energy system configurations in 2050. The method used included the estimation of the storage capacity of salt caverns in bedded rock salt deposits and salt domes and selected structures in deep aquifers. An estimation showed a large hydrogen storage potential of geological structures. In the case of analyzed bedded rock salt deposits and salt domes, the average storage capacity per cavern is 0.05–0.09 TWhH2 and 0.06–0.20 TWhH2, respectively. Hydrogen storage capacity in analyzed deep aquifers ranges from 0.016 to 4.46 TWhH2. These values indicate that in the case of the upper bound for storage demand, there is a need for the 62 to 514 caverns, depending on considered bedded rock salt deposits and salt domes or the 9 largest analyzed structures in deep aquifers. The results obtained are relevant to the discussion on the global hydrogen economy, and the methodology can be used for similar considerations in other countries.

Efficient hydrogen generation of ammonia borane by direct heat supply using a polyimide film heater

This study developed a novel approach to ammonia borane (AB) and silica assembly for all-solid-state thermal dehydrogenation, which can be integrated into current hydrogen generation systems. The AB/silica assembly apparatus is created by attaching pelletized AB specimens to both sides of a polyimide film heater, thus facilitating direct heat supply. The temperature, pressure, and power consumption data of the heater demonstrate that the dehydrogenation reaction is completed within 2 min from the initiation of the electric heating signal. Notably, the temperature and pressure of the generated hydrogen gas reach 39.5 °C and 1.95 barg, respectively, and the maximum hydrogen yield reached 11.46 wt% during the experiment. The infrared spectroscopy analysis indicates that all AB/silica samples inside the assembly undergoes complete reaction. This direct heating method significantly reduces the energy required for AB thermal decomposition and it increases the amount of AB that can be used at once.

Application of machine learning in evaluating and optimizing the hydrogen production performance of a solar-based electrolyzer system

A green hydrogen production method based on solar energy is proposed, and Machine Learning (ML) models are adopted for system optimization. This study assayed to highlight the potential of using ML in anticipating the performance of a Photovoltaic Thermal (PVT) system integrated with an electrolyzer device. For this purpose, the performance of four different ML models, including Extreme Learning Machine (ELM), Convolutional Neural Network (CNN), Gated Recurrent Unit (GRU), and CatBoost, in predicting the hydrogen production of the solar-based system are analyzed. The hyperparameters of the ML models are optimized using the Arithmetic Optimization Algorithm (AOA). Furthermore, the optimum performance of the system is obtained by implementing the Multi-Objective Grey Wolf Optimizer (MOGWO). The outcomes reveal that the AOA-CatBoost is the most accurate ML model in predicting the performance of the system. This model forecasts that the maximum hydrogen production rates of the system in the seasons of spring, summer, fall, and winter are respectively 2.10 mol/h, 2.22 mol/h, 1.93 mol/h, and 1.87 mol/h. Besides, the MOGWO shows that the maximum amount of hydrogen production and electrical generation of the system are 24.48 mol/day and 7.74 MJ/day, respectively.

Hydrogen generation by hydrolysis of ultrafine microstructure Mg[sbnd]10Ni alloy wire

This work presents a MgNi alloy wire prepared by a combination of extrusion and multi-pass hot drawing for fast hydrogen generation from aqueous NaCl solution. The results showed that the hydrogen generation rates of the wire were significantly improved compared to the as-cast alloy. The hydrolysis of the MgNi alloy wire produced 820 ml g−1 hydrogen in 16 min and the maximum hydrogen generation rates reached 67.86 ml g−1 min−1 in 3.5 % NaCl solution and at 25 °C. The improved hydrogen production properties can be attributed to the increase in specific surface area and the ultrafine microstructure with highly dispersed submicron Mg2Ni particles of the MgNi alloy wire.

Co-digestion of solid-liquid waste from citrus agroindustrial: Effect of hydraulic retention time and organic loading rate on H2 production in a long-term continuous operation leach bed reactor

The Leach Bed Reactor (LBR) application is a promising alternative for the anaerobic digestion of solid waste and wastewater. In this study, the LBR was continuously operated for 160 days in four different phases, for co-fermentation of solid and liquid waste from the citrus agroindustry, at 37 °C, evaluating the effect of hydraulic retention time (HRT) and organic loading rate (OLR). The maximum volumetric hydrogen production (VHPR) was observed at an HRT of 12h (958.3 mLH2.L-1.d-1); however, the highest hydrogen yield (HY) was identified at an HRT of 24h (104.9 mLH2.g-1CHO). Based on the metabolic characteristics of microorganisms identified in higher relative abundance, by 16S rRNA sequencing, such as Lactobacillus, Caproicoproducens, Bifidobacterium, Olsenella, and Solobacterium, an occurrence of chain elongation pathways in the production of butyric and caproic acids was inferred, with hydrogen production resulting from the lactic acid oxidation. The maximum electricity production potential of 16.3 kWh.m-3 liquor was estimated.

Atomistic Investigation of the occupancy limits and stability of hydrogen hydrates as a hydrogen storage medium

Gas hydrates are nonstoichiometric inclusion compounds which occur via a hydrogen bonded water network. This network forms cages that encapsulates gas molecules such as hydrogen which are stabilized by weak van der Waals forces. This unique cage-guest interaction offers the potential for a safe, economical, and green medium for hydrogen storage. In this study, we use Density Functional Theory (DFT) to investigate the storage capacity of hydrates which primarily depends on the hydrogen occupancy in the small and large cages of the lattice structure. Energy analysis of the system with various occupancies shows that DFT is indicating occupancy limits beyond what has been previously reported and that the maximum occupancy in small and large cages is interdependent. The maximum hydrogen occupancy is 9 in large cages with an occupancy of 1 and 2 in the small cages and a maximum of 8 with an occupancy of 3 or 4 in the small cages. The occupancy limit mechanism is the breakage of hydrogen bonds due to cage volume expansion, the diffusion of hydrogen through pentagonal and hexagonal faces in small and large cages, and computational convergence.

Multi-criteria site selection workflow for geological storage of hydrogen in depleted gas fields: A case for the UK

Underground hydrogen storage (UHS) plays a critical role in ensuring the stability and security of the future clean energy supply. However, the efficiency and reliability of UHS technology depend heavily on the careful and criteria-driven selection of suitable storage sites. This study presents a hybrid multi-criteria decision-making framework integrating the Analytical Hierarchy Process (AHP) and Preference Ranking Organisation Method for Enrichment of Evaluations (PROMETHEE) to identify and select the best hydrogen storage sites among depleted gas reservoirs in the UK. To achieve this, a new set of site selection criteria is proposed in light of the technical and economic aspects of UHS, including location, reservoir rock quality and tectonic characteristics, maximum achievable hydrogen well deliverability rate, working gas capacity, cushion gas volume requirement, distance to future potential hydrogen clusters, and access to intermittent renewable energy sources (RESs). The framework is implemented to rank 71 reservoirs based on their potential and suitability for UHS. Firstly, the reservoirs are thoroughly evaluated for each proposed criterion and then the AHP-PROMETHEE technique is employed to prioritise the criteria and rank the storage sites. The study reveals that the total calculated working gas capacity based on single-well plateau withdrawal rates is around 881 TWh across all evaluated reservoirs. The maximum well deliverability rates for hydrogen withdrawal are found to vary considerably among the sites; however, 22 % are estimated to have deliverability rates exceeding 100 sm3/d, and 63 % are located within a distance of 100 km from a major hydrogen cluster. Moreover, 70 % have access to nearby RESs developments, with an estimated cumulative RESs capacity of approximately 181 GW. The results highlight the efficacy of the proposed multi-criteria site selection framework. The top five highest-ranked sites for UHS based on the evaluated criteria are the Cygnus, Hamilton, Saltfleetby, Corvette, and Hatfield Moors gas fields. The insights provided by this study can contribute to informed decision-making, sustainable development, and the overall progress of future UHS projects within the UK and globally.

European Green Deal: An Experimental Study of the Biomass Filtration Combustion in a Downdraft Gasifier

This study presents the experimental results obtained from hybrid filtration combustion using biomass pellets. The experiments were carried out using a porous media gasifier filled with pellets and inert material. The gasifying agent used was an air–steam mixture, with 40% being steam. The dependence of the temperature in the gasifier’s reaction zone from the volume percentage of inert porous material in the gasifier, the specific heat capacity of this material, as well as the air–steam blowing rate, was investigated. The multifactor experiment method was used. A maximum temperature of 1245 °C was achieved using 28 vol% of porous material with a heat capacity of 1000 J/(kg·°C) and at a blowing rate of 42 m3/h. The maximum hydrogen content in the syngas was 28 vol%. This was achieved at an air–steam blowing rate of 42 m3/h and 40 vol% porous material, with a heat capacity of 1000 J/(kg·°C). The calorific value of the syngas was 12.6 MJ/m3. The highest CO content in the gas was 28 vol% and was obtained at 20 vol% porous material with a heat capacity of 1000 J/(kg·°C) and a blowing rate of 42 m3/h. The obtained information is applicable in the design, management, and control of gas production by way of a hybrid filtration combustion process in a downdraft gasifier.

Techno‐economic viability analysis of a downdraft gasification system for hydrogen production from date molasses waste in Iraq

AbstractIn the current study, a fixed‐bed downdraft gasifier was used, in addition to gas cleaning and treatment units, to evaluate hydrogen production from the waste from a date molasses factory. Date pits and pomace were gasified at a temperature of 800°C with oxygen‐rich air and standard air as the gasifying agents. Simulations were performed using the Cycle‐Tempo simulation tool. The impact of many process parameters (air–fuel ratio, gasification temperature, moisture content, oxygen concentration and temperature of the water–gas shift) on gas composition was investigated. The economic evaluation of hydrogen production is also discussed in this paper. Depending on the operating conditions, the results indicate that gasification of biomass in oxygen‐rich air improves hydrogen yield compared with air gasification of biomass. Over the range of operating conditions examined, the maximum hydrogen production reached 45.86% for pits and 35.81% for pomace from gasification with oxygen‐rich air while the H2 content reached 36.71 and 28.72% respectively for air gasification of pits and pomace. The cost analysis for the date waste gasification unit showed that the hydrogen production cost is $3/kg for date pits and $4/kg for pomace. The production of hydrogen from date molasses manufacturing waste helps to lessen reliance on fossil fuels and is an environmentally beneficial alternative source of renewable energy.

Operational and design parameters evaluation to improve hydrogen production using a low-cost alkaline water electrolysis cell in direct combination with a photovoltaic cell

Hydrogen production from renewable sources such as photovoltaic solar energy can contribute to a more sustainable energy scenario worldwide. The present work aimed to evaluate hydrogen production via alkaline water electrolysis by finding the optimal operational conditions with electrodes, alkaline electrolyzers, and solar energy with a photovoltaic panel. Firstly, graphite, stainless steel 304, and Monel 400 electrodes were evaluated using a direct voltage source, resulting in maximum hydrogen flow rates of 4.86, 10.40, and 8.12 mL/min, respectively. Then, hydrogen generation was analyzed with electrolytes of KOH, NaOH, and LiOH in 1-10 mol/L concentrations. The highest hydrogen flow rates were found for KOH electrolytes, attributed to their higher electrical conductivity. Therefore, stainless steel electrodes and KOH electrolyte were evaluated with the photovoltaic panel. The optimized conditions were a KOH concentration of 6.18 mol/L and a solar radiation of 900 W/m2 for a hydrogen production of 71.83 mL/min. The hydrogen purity remained at 98.96 ± 0.10%.

Nitrogen and sulfur co-doped coal-based carbon quantum dots enhance the photocatalytic hydrogen evolution of Co-Fe-P derived from MOF

In order to explore the functional application of coal and realize the high-value application of low-quality coal. Therefore, low-cost coal as a carbon source into environmental protection, high-value coal-based carbon quantum dots (CQDs). This study employed high-sulfur coal as the carbon source and urea as the nitrogen source to successfully synthesize nitrogen and sulfur co-doped coal-based carbon quantum dots (NSCQDs) via a one-pot hydrothermal method. These NSCQDs were utilized as co-catalysts to assist the photocatalytic water splitting and hydrogen evolution of metal phosphides (Co-P and Fe-P). The obtained catalysts were subjected to systematic structural and property analyses, and the photocatalytic hydrogen evolution activity and stability were investigated, along with an analysis of the photocatalytic mechanism. The results revealed that the novel composite photocatalyst exhibited high hydrogen evolution activity, with a maximum hydrogen evolution rate of 28.41 mmol·g−1·h−1 at pH 10. Under a wavelength of 520 nm, the apparent quantum efficiency (AQE) reached 4.93%, and the solar-to-hydrogen (STH) conversion efficiency reached 0.46%. The semiconductor type (n-type) of the monophasic catalyst was determined through Mott-Schottky analysis, and the band structure was analyzed accordingly. The conduction and valence band positions for Co-P were determined to be -0.44 eV and 1.31 eV, respectively, while those for Fe-P were found to be -0.51 eV and 1.17 eV, respectively. Based on these results, it is inferred that an S-type heterojunction is formed between Co-P and Fe-P, and NSCQDs enhanced photocatalytic hydrogen evolution as an auxiliary catalyst. This research advances the synthesis of coal-based carbon quantum dots and provides the key information for the photocatalytic decomposition of water and hydrogen evolution using coal-based CQDs.

Performance analysis and optimization of a TEG-based compression hydrogen storage waste heat recovery system

A considerable quantity of waste heat is produced while compressing hydrogen. The process can be optimized by converting heat energy into electricity by utilizing thermoelectric electricity generator (TEG). This paper presents a TEG-based compression hydrogen storage waste heat recovery system (TEG-CHWSR). The effects of compression ratio, mass flow rate and inlet temperature at the cold and hot side on the operation performance and energy recovery efficiency are studied by establishing a mathematical model. The results demonstrate that the hydrogen inlet temperature and mass flow rate significantly impact the maximum output power and corresponding conversion efficiency of TEG. The maximum hydrogen storage pressures corresponding to the four types of hydrogen storage tanks are different. The maximum output power range of TEG for four hydrogen storage tanks is 2.32–5.9 kW at the TEG length of 1 m. The maximum output power and optimal module length increase with the increased hydrogen mass flow rate, while the energy recovery efficiency firstly increases and then decreases, existing a maximum point. The inlet temperature and mass flow rate at cold side has little influent on the optimal length of the TEG module. However, it has impact on the output power and thermoelectric conversion efficiency of TEG.

Modified carbon paste electrode with choline proline in enhancing the performance of water electrolysis system for hydrogen production

Hydrogen has been under the light to be one of the future energy prospects to replace the non-renewable energy sources such as fossil fuels and natural gas. The drawbacks of the conventional methods in hydrogen production are the large emission of greenhouse gases (GHGs) associated with the process that required a highly cost CO2 sequestration method to reduce substantially the emission. Therefore, this study focusses on the hydrogen production rate as well as power consumption per hydrogen produced through water splitting process. This study also emphasizes the utilization of carbon paste electrode (CPE) as the electrode in the water electrolysis system with the modification of CPE by the addition of amino acid-based ionic liquid (AAIL). Prior to the modification of CPE, choline proline [Ch][Pro] has been determined as the most suitable modifier for CPE through chemical quantum approach via Conductor-like Screening Model for Realistic Solvents. As the modification of CPE, the best optimum composition of paraffin oil to [Ch][Pro] was 90 vol% of paraffin oil to 10 vol% of [Ch][Pro] which can produce the maximum hydrogen production of 18.2 mL/h with the power consumption of 249.3 kWh/kg H2 as compared to CPE without IL modification with merely 8.0 mL/h of hydrogen production and power consumption of 378.1 kWh/kg H2.

Hydrogen embrittlement behavior of two mining chain steels by slow strain rate test

Two mining chain steels 23MnNiMoCr5-4 and 0.3C0.2Si0.3Mn4.2(Cr+Ni+Mo) with tensile strengths of 1200 MPa and 1250 MPa, respectively, were employed to investigate their hydrogen embrittlement behaviors by slow strain rate tests combined with thermal desorption analyses. It is shown that at initial stage the fracture stress decreases linearly as the hydrogen content increases, and the turning points occur at hydrogen content of 1.2 wppm for 0.3C0.2Si0.3Mn4.2(Cr+Ni+Mo) and 0.26 wppm for 23MnNiMoCr5-4. The fractured surface observation suggests that the ratio of intergranular fracture area to quasi-cleavage area increases dramatically at the turning points. The maximum hydrogen contents resulting from the corrosive HCl solutions with pHs of 2 are approximately 0.6 wppm 0.3C0.2Si0.3Mn4.2(Cr+Ni+Mo) and 0.11 wppm for 23MnNiMoCr5-4, corresponding to the activation energies for hydrogen desorption are 21.57 kJ/mol and 14.53 kJ/mol, respectively.

Dandelion-like ZIF-67 supported ternary transition metal borides as efficient hydrolysis catalysts for KBH4

The development of high-efficient and low-cost catalysts is crucial for promoting KBH4 hydrolysis to produce hydrogen. Herein, ZIF-67 supported cobalt-molybdenum-nickel based boride (Co–Mo–Ni–B/ZIF-67) nanocomposites with dandelion-like morphology were designed as catalysts of KBH4 hydrolysis reaction and were synthesized via the chemical reduction process. Moreover, the element ratio and the loading amount of Co–Mo–Ni–B were optimized, and effects of KBH4 concentration, KOH concentration, and reaction temperature on catalytic performances were studied. As expected, ZIF-67 substrate avoids the agglomeration of amorphous Co–Mo–Ni–B, and the synergy between ZIF-67 and uniformly dispersed Co–Mo–Ni–B active substances accelerates hydrogen generation rate. As a result, the maximum hydrogen generation rate of 17400 mL min−1 g−1 is achieved with the optimized KOH concentration of 10% and KBH4 concentration of 6% at the reaction temperature of 30 °C. In addition, Co–Mo–Ni–B/ZIF-67 exhibits moderate durability performance with a cyclic retention rate of 51.9 % after five cycles. This dandelion-like structure design provides an idea for the development of efficient catalyst for hydrolysis of borohydrides.

Selectivity enhancement by the presence of HOF + CNT composite membranes investigated by non-equilibrium molecular dynamics

Hydrogen purification through membrane separation offers convenience and suitability for on-site operation, especially in automotive fuel cells that utilize reformed methanol as a hydrogen source. In this study, the molecular dynamics simulation method was employed to investigate the micro-separation mechanism of hydrogen purification using multi-walled carbon nanotubes (MWNTs) and hydrogen-bonded organic frameworks (HOFs) as membrane materials. Novel composite membranes combining different HOF and MWNT materials were designed to enhance the interaction energy with CO2. The results demonstrated that these composite membranes exhibited higher selectivity in the separation of H2/CO2 gas mixtures, achieving higher hydrogen permeability compared with individual HOF and MWNT membranes. Notably, the PhTCz1 + CNT, UPC-H4a + CNT, and TCPP-1,3-DPP + CNT-3 composite membranes demonstrated 100 % CO2 retention and reached a maximum flux hydrogen of 4.782 × 105 GPU, which was higher than traditional membranes by 6 orders of magnitude. Furthermore, the PhTCz1 + CNT-3 composite membrane had a significant ability to simultaneously intercept CO2 and CO. The MD calculation results show that this newly synthesized HOF + CNT composite membrane material can provide high permeability as well as ultrahigh selectivity simultaneously, making it a prospective H2 separation membrane with superior performance.