Hydrogen Production Technologies Research Articles

Rapid Scalable One‐step Production of Catalysts for Low‐Iridium Content Proton Exchange Membrane Water Electrolyzers

AbstractProton exchange membrane water electrolysis (PEMWE) is a promising technology for green hydrogen production, although its widespread development with state‐of‐the‐art loadings is threatened by the scarcity of iridium (Ir). Homogeneous dispersion of Ir in an immiscible electro‐ceramic matrix can enhance catalytic mass activity and structural stability. The study presents IrySn0.9(1−y)Sb0.1(1−y)Ox solid solutions produced by highly scalable flame spray pyrolysis (FSP) process as efficient anode electrocatalysts for PEMWE, containing only 0.2 mg cm−2 of Ir in the catalyst layer (CL). Intense mixing of metal vapor and large thermal gradients in the precursor‐derived high‐temperature flame aids stabilizing sub‐nanoscale entropic mixing within self‐preserved 4–6 nm particles. Detailed investigations confirm that the one‐step prepared solid solution electrocatalysts exhibit up to fourfold higher activity toward the oxygen evolution reaction (OER) compared to Ir black. The anode of a PEMWE utilizing this catalyst exhibits high performance and stability over 2000 h but with tenfold lower Ir loading than the state‐of‐art.

Self-sacrificing and self-supporting biomass carbon anode–assisted water electrolysis for low-cost hydrogen production

Electrooxidation of renewable and CO2-neutral biomass for low-cost hydrogen production is a promising and green technology. Various biomass platform molecules (BPMs) oxidation assisted hydrogen production technologies have obtained noticeable progress. However, BPMs anodic oxidation is highly dependent on electrocatalysts, and the oxidation mechanism is ambiguous. Meanwhile, the complexity and insolubility of natural biomass severely constrain the efficient utilization of biomass resources. Here, we develop a self-sacrificing and self-supporting carbon anode (SSCA) using waste corncobs. The combined results from multiple characterizations reveal that the structure-property-activity relationship of SSCA in carbon oxidation reaction (COR). Theoretical calculations demonstrate that carbon atoms with a high spin density play a pivotal role in reducing the adsorption energy of the reactive oxygen intermediate (*OH) during the transition from OH- to *OH, thereby promoting COR. Additionally, the HER||COR system allows driving a current density of 400 [Formula: see text] at 1.24 V at 80 °C, with a hydrogen production electric consumption of 2.96 kWh Nm-3 (H2). The strategy provides a ground-breaking perspective on the large-scale utilization of biomass and low-energy water electrolysis for hydrogen production.

Techno-economic analysis of green hydrogen integration into existing pipeline infrastructure: A case study of Wyoming

While green hydrogen production technologies like electrolysis have reached commercial scale, the primary challenge centers on efficient, and economically viable transportation of hydrogen. This study proposes an integrated geospatial techno-economic modeling approach to optimize hydrogen transportation through blending in existing pipelines. The simulations strategically locate green hydrogen production and blending points. The paper evaluates blending ratios, flow dynamics, and operating parameters to optimize hydrogen blending in natural gas pipelines. A techno-economic analysis quantifies costs and revenues across the supply chain, identifying the most economically viable hydrogen blending locations. The approach is validated through a case study in Wyoming, providing insights for industry stakeholders considering hydrogen-natural gas blending as a transition strategy. This integrated method offers a robust decision support tool for leveraging existing infrastructure to realize hydrogen's potential as a sustainable energy vector contributing to the broader goal of cleaner energy alternatives.

Exploiting the Ocean Thermal Energy Conversion (OTEC) technology for green hydrogen production and storage: Exergo-economic analysis

This study presents and analyses three plant configurations of the Ocean Thermal Energy Conversion (OTEC) technology. All the solutions are based on using the OTEC system to obtain hydrogen through an electrolyzer. The hydrogen is then compressed and stored. In the first and second layouts, a Rankine cycle with ammonia and a mixture of water and ethanol is utilised respectively; in the third layout, a Kalina cycle is considered. In each configuration, the OTEC cycle is coupled with a polymer electrolyte membrane (PEM) electrolyzer and the compression and storage system. The water entering the electrolyzer is pre-heated to 80 °C by a solar collector. Energy, exergy, and exergo-economic studies were conducted to evaluate the cost of producing, compressing, and storing hydrogen. A parametric analysis examining the main design constraints was performed based on the temperature range of the condenser, the mass flow ratio of hot and cold resource flows, and the mass fraction. The maximum value of the overall exergy efficiency calculated is equal to 93.5% for the Kalina cycle, and 0.524 €/kWh is the minimum cost of hydrogen production achieved. The results were compared with typical data from other hydrogen production systems.

Membrane reformer technology for sustainable hydrogen production from hydrocarbon feedstocks

Hydrogen (H2) is receiving growing interest as a clean energy carrier as the world’s energy system transitions towards net zero. Today, H2 is primarily produced from hydrocarbons using the steam methane reforming (SMR) process. This well-established method converts methane-rich gas into syngas, which is further treated with steam to increase H2 yield via the water-gas-shift (WGS) process. However, this conventional route results in high carbon intensity of 10 tons CO2/ton of H2. Therefore, there is a growing need for sustainable H2 production technologies that utilize existing fossil energy sources and infrastructure while minimizing carbon emissions and costs.Membrane reactors (MR) are a promising technology for sustainable H2 production from hydrocarbons. A H2-selective palladium-alloy (Pd–Au) membrane is integrated within the catalyst bed, creating a system where H2 production and separation occur simultaneously in a single unit. This integration offers several advantages over the conventional system; process intensification allows thermodynamic equilibrium conversion limitations to be overcome while producing high purity (>99%) H2 at milder operating temperatures of ∼550 °C compared to 800–1000 °C in conventional packed bed reactors. Downstream processes such as WGS reactors and pressure swing adsorption are eliminated, resulting in reduced capital and operating costs. Moreover, the by-product stream remains pressurized at 25–40 bar and contains CO2 at concentrations above 60%, enabling CO2 capture at reduced cost.

Graphitic carbon nitride nanosheets decorated with HAp@Bi2S3 core–shell nanorods: Dual S-scheme 1D/2D heterojunction for environmental and hydrogen production solutions

By combining different semiconductors, scientists have developed innovative materials capable of converting solar energy into useful forms of energy or driving chemical reactions that clean up pollutants. These materials offer a promising path to combat global environmental and energy challenges. In this study, HAp@Bi2S3 core–shell structures were synthesized using a facile microemulsion technique, and then loaded onto graphitic carbon nitride via a hydrothermal method to create an advanced HAp@Bi2S3/g-C3N4 dual S-scheme heterojunction. The engineered heterojunction exhibited enhanced hydrogen production and visible light photocatalytic oxidation of metronidazole. The improved photocatalytic efficiency was attributed to the core–shell structure of HAp@Bi2S3 along with the formation of a dual S-scheme heterojunction in HAp@Bi2S3/g-C3N4. As a result, the novel dual S-scheme HAp@Bi2S3/g-C3N4 heterojunction demonstrated a significantly higher hydrogen production rate, ca. 20 times higher than that of hydroxyapatite (HAp), 11 times higher than Bi2S3, and 5 times higher than the HAp@Bi2S3. This research introduces a novel approach to crafting dual S-scheme heterojunctions based on Bi2S3, which enables swift electron transfer across heterojunction interfaces, thereby enlarged possibility windows to sustainable hydrogen production and wastewater remediation technologies.

Construction of Co-Ni3B/GDY heterostructured electrocatalyst for boosting oxygen evolution in alkaline media

Water splitting as the clean technology for hydrogen production garnered the widespread attention. The high overpotential required for oxygen evolution reaction (OER) is the central dilemma. Herein, Co-Ni3B/graphdiyne heterostructure on copper foam (Co-Ni3B/GDY/CF) was constructed for boosting alkaline OER. Detailed electrochemical analysis showed that Co-Ni3B/GDY/CF was an exceptional OER electrocatalyst with the low overpotentials of 270 and 335mV at 20 and 100mAcm−2 in 1.0M KOH solution, respectively, as well as high turnover frequency of 0.80s−1 at 400mV. Moreover, its catalytic performance outperformed the benchmarked RuO2/CF when the current density exceeded 200mAcm−2. Importantly, the equipped electrolyser Pt/C/CF||Co-Ni3B/GDY/CF showed low cell voltage (1.53V@10mAcm−2) and long-term durability. These results demonstrated that a synergistic effect at the heterointerface between GDY and Co-Ni3B was achieved, which regulated the electronic configuration, accelerated the charge transfer and increased the active surface areas. Furthermore, the density functional theory calculations revealed that Co-Ni3B/GDY with incomplete charge transfer lowered the energy barrier of the rate-determining step and optimized adsorption/desorption behavior of the intermediates, thereby effectively promoting O2 evolution.

Investigation of the flash vaporization technique as a novel anolyte separation method in a copper-chlorine thermochemical cycle for sustainable hydrogen production

Thermochemical water-splitting processes are a promising alternative to the conventional hydrogen production technologies. In this regard, the thermochemical copper-chlorine cycle is amongst the clean hydrogen production processes that have shown immense promise to achieve commercialization in the long term future through several investigations reported in the open literature. A primary reason for this is its moderate temperature requirements which can be harnessed through a wide variety of sources such as waste heat or solar thermal energy. More specifically, the four-step variant of the copper-chlorine cycle has exhibited the highest efficiencies compared to its three and five-step versions. However, certain aspects of the cycle need further attention. One such aspect is the fourth and the final step of the cycle – the anolyte separation step which ensures the complete replenishment of all chemical compounds within the cycle. The anolyte is a homogeneous solution that constitutes water, hydrochloric acid, copper (II) chloride, and copper (I) chloride. The existing methodology for the separation of all these chemicals considers a multi-step drying process that takes place at ambient pressure and temperatures over 100°C. These conditions have been concluded to contribute to lowering the energy efficiency and increasing the cost rate of hydrogen through various studies previously conducted and published by the authors. In this regard, the authors have investigated an alternative technique for the anolyte separation process – the flash vaporization method where the partial separation of various chemical species can be achieved under vacuum conditions resulting in lower required temperatures and ultimately making the anolyte separation process relatively less energy intensive. Thus, this paper develops a stand-alone experimental set-up to investigate the flash vaporization process on a lab scale to determine its feasibility and potential to be a replacement for the existing approach of anolyte separation in a four-step copper-chlorine thermochemical cycle. The experiments are conducted under a wide variety of conditions and the obtained results are quite promising. Further, this study also considers the development of an empirical model to enable an analytical quantitative prediction of the separated anolyte solution.

The influence of operating parameters on the performance of PEMWE electrolytic cell

Proton exchange membrane (PEM) is considered the most promising green hydrogen production technology in the future. The proton exchange membrane electrolysis cell (PEMEC) involves a complex process of multiple physical fields, including charge transfer, gas transfer, and heat transfer, during operation. Increasing the inlet water flow rate within a certain range is beneficial for increasing the output performance of the electrolysis cell and can also reduce the average temperature of the proton exchange membrane. But when the inlet flow rate increases to a certain amount, it has no effect. As the electrolysis voltage increases, the electrochemical performance of the electrolysis cell also increases, and the temperature of the proton exchange membrane and the current density of the catalytic layer also increase with the increase of voltage.

Optimization of Hydrogen Production System Performance Using Photovoltaic/Thermal-Coupled PEM

A proton exchange membrane electrolyzer can effectively utilize the electricity generated by intermittent solar power. Different methods of generating electricity may have different efficiencies and hydrogen production rates. Two coupled systems, namely, PV/T- and CPV/T-coupling PEMEC, respectively, are presented and compared in this study. A maximum power point tracking algorithm for the photovoltaic system is employed, and simulations are conducted based on the solar irradiation intensity and ambient temperature of a specific location on a particular day. The simulation results indicate that the hydrogen production is relatively high between 11:00 and 16:00, with a peak between 12:00 and 13:00. The maximum hydrogen production rate is 99.11 g/s and 29.02 g/s for the CPV/T-PEM and PV/T-PEM systems. The maximum energy efficiency of hydrogen production in CPV/T-PEM and PV/T-PEM systems is 66.7% and 70.6%. Under conditions of high solar irradiation intensity and ambient temperature, the system demonstrates higher total efficiency and greater hydrogen production. The CPV/T-PEM system achieves a maximum hydrogen production rate of 2240.41 kg/d, with a standard coal saving rate of 15.5 tons/day and a CO2 reduction rate of 38.0 tons/day. Compared to the PV/T-PEM system, the CPV/T-PEM system exhibits a higher hydrogen production rate. These findings provide valuable insights into the engineering application of photovoltaic/thermal-coupled hydrogen production technology and contribute to the advancement of this field.

Evaluation of sustainable hydrogen production technologies by fuzzy AHP analysis with bootstrapping

The concept of a hydrogen economy has received increasing attention worldwide. Hydrogen is a promising energy carrier that contributes to the development of a sustainable and reliable energy sector. Selection of the most sustainable hydrogen production technology (HPT) plays a significant role in promoting a hydrogen economy. However, it is regarded as a multi-criteria decision-making (MCDM) problem with several incompatible evaluation criteria. In this study, we develop an MCDM approach based on Fuzzy Analytic Hierarchy Process (FAHP) for prioritizing HPT alternatives, focusing on Egypt as a case study. Our contributions are twofold. First, to combat the issue of a small number of subject matter experts, a bootstrap method is employed to validate the main criteria weights in FAHP. Second, we conduct a comparative FAHP analysis from a broad perspective of the national experts from a developing country and the international experts from developed countries. Our results show that PV electrolysis is the most preferable technology option from the perspectives of both the national and international experts. Since the FAHP approach proposed is a flexible framework that can be applied to countries other than Egypt, it will support global policymakers and industry stakeholders in their decision making toward a sustainable and efficient hydrogen economy strategy.

Progress on Si‐based photoelectrodes for industrial production of green hydrogen by solar‐driven water splitting

AbstractSolar power has been regarded as the ultimate green‐energy source because of its inexhaustibility and eco‐friendliness. The solar‐driven water‐splitting technology for green hydrogen production is considered to be one of effective ways for solar energy harvesting and storage, which may provide solutions for the energy crisis and environmental issues. In the past decades, great progress has been achieved in this area. Photoelectrochemical (PEC) water splitting is especially promising for the production of solar fuels because of expected large‐scale industrial application. Silicon (Si), as an ideal candidate for the photoelectrode, is the most suitable material for the PEC device in industrial photocatalytic water splitting because of its abundance, mature fabrication technology, and suitable band gap. Here, we give a systematic review on the recent progress for Si‐based photoelectrodes for water splitting with a focus on the industrial application. Particularly, the strategies, such as band‐alignment control, morphology design, and surface engineering, are summarized to enhance the PEC performance and durability for practical application. Furthermore, the perspective for the design of commercial Si‐based PEC devices with high PEC performance, long‐term stability, large‐size, and low cost are given at the end, which shall guide the development of PEC water splitting for industrial application.

Control Structures for Combined H2/Electricity from Offshore Wind Turbines

Wind energy proves to be a highly favourable choice for electricity generation due to its clean and renewable nature, and is playing a significant role in reducing global greenhouse gas emissions. Offshore wind turbine systems have gained widespread popularity as they can capitalise on elevated and consistent wind speeds surpassing those found in onshore locations, resulting in increased energy efficiency. Furthermore, offshore wind power possesses the potential to emerge as a significant electricity source for the production of green hydrogen. As water electrolysis technology for hydrogen production continues to advance, utilizing offshore wind power for hydrogen generation is becoming more economically viable and practical. Offshore wind power with higher wind speeds in combination with efficient control structures presents an attractive option for electricity generation and hydrogen co-production. This paper aims to present and evaluate four different production structures for combined H2/energy generation from offshore wind turbines. Previous research studies in this area often overlook control structures and lack information on power converter operations. In contrast, this article studies control structures that enable proper functionality and ensure adequate interoperability, enhancing the reliability of renewable energy integration. Each structure, including both wind turbines and electrolyser, is described in detail, along with the corresponding controllers. Simulation results are presented for each structure and controller to demonstrate their effective operation.

Greenhouse gas emissions and net energy production of dark fermentation from food waste followed by anaerobic digestion

There are diverse estimations regarding the carbon reduction effects of alternative hydrogen production technologies. This study assessed the greenhouse gas (GHG) emissions and energy balance of a two-stage process combining dark fermentative hydrogen production and anaerobic digestion from food waste using the cradle-to-gate life cycle assessment (LCA). The system boundary included collection and transportation, pretreatment and feedstock storage, dark fermentation, H2 purification, anaerobic digestion and heat and power generation and the estimated GHG emission was compared with a single anaerobic digestion of food waste. GHG emission of the biohydrogen production was estimated as 2.48 kg CO₂-eq per kg H₂ without considering avoided emissions from heat and power generation. The environmental impacts were majorly influenced by electricity use. The net energy ratio of the two-stage process was calculated to be 8.18, confirming a net energy gain and the potential GHG emission avoidance for electricity and heat use. Given that the single-stage anaerobic digestion of 16 tons of food waste is replaced by the two-stage dark fermentation process, 76.6 kg CO₂-eq would be avoided. Sensitivity analysis revealed that energy-saving strategies are the most sensitive factors for achieving positive net energy production and low global warming potential.

Proton exchange membrane‐based electrocatalytic systems for hydrogen production

AbstractHydrogen energy from electrocatalysis driven by sustainable energy has emerged as a solution against the background of carbon neutrality. Proton exchange membrane (PEM)‐based electrocatalytic systems represent a promising technology for hydrogen production, which is equipped to combine efficiently with intermittent electricity from renewable energy sources. In this review, PEM‐based electrocatalytic systems for H2 production are summarized systematically from low to high operating temperature systems. When the operating temperature is below 130°C, the representative device is a PEM water electrolyzer; its core components and respective functions, research status, and design strategies of key materials especially in electrocatalysts are presented and discussed. However, strong acidity, highly oxidative operating conditions, and the sluggish kinetics of the anode reaction of PEM water electrolyzers have limited their further development and shifted our attention to higher operating temperature PEM systems. Increasing the temperature of PEM‐based electrocatalytic systems can cause an increase in current density, accelerate reaction kinetics and gas transport and reduce the ohmic value, activation losses, ΔGH*, and power consumption. Moreover, further increasing the operating temperature (120–300°C) of PEM‐based devices endows various hydrogen carriers (e.g., methanol, ethanol, and ammonia) with electrolysis, offering a new opportunity to produce hydrogen using PEM‐based electrocatalytic systems. Finally, several future directions and prospects for developing PEM‐based electrocatalytic systems for H2 production are proposed through devoting more efforts to the key components of devices and reduction of costs.

Current Status of Green Hydrogen Production Technology: A Review

As a clean energy source, hydrogen not only helps to reduce the use of fossil fuels but also promotes the transformation of energy structure and sustainable development. This paper firstly introduces the development status of green hydrogen at home and abroad and then focuses on several advanced green hydrogen production technologies. Then, the advantages and shortcomings of different green hydrogen production technologies are compared. Among them, the future source of hydrogen tends to be electrolysis water hydrogen production. Finally, the challenges and application prospects of the development process of green hydrogen technology are discussed, and green hydrogen is expected to become an important part of realizing sustainable global energy development.

Predictive modeling of membrane reactor efficiency using advanced artificial neural networks for green hydrogen production

The imperative to decarbonize the energy sector has prompted substantial advancements in clean electricity generation, with hydrogen emerging as a promising low-carbon energy carrier. While hydrogen synthesis from renewable sources is crucial, challenges persist, necessitating innovative approaches for efficient and sustainable production. This study leverages diverse artificial neural network (ANN) models to assess and predict system efficiency based on key operational variables in membrane reactor systems. The multilayered perceptron (MLP) and radial basis function (RBF) methodologies are employed, with the MLP models optimized across twelve training algorithms and eight activation functions, exploring up to three hidden layers with variable neuron counts. The MLP model, utilizing the Levenberg-Marquard training algorithm and Tangent-Sigmoid activation function, achieved a high correlation coefficient (R2) of 0.9975 for training and 0.9962 for testing, and a mean squared error (MSE) of 0.00425 for training and 0.23951 for testing, indicating precise and accurate efficiency predictions. The Log-Sigmoid activation function also performed well, with R² values of 0.9971 (training) and 0.9961 (testing), and MSE values of 0.004086 (training) and 0.17694 (testing). Optimization of the RBF network identified the best performance with a spread parameter of 1 and 35 neurons, although the MLP model demonstrated superior accuracy and reduced computational time. Statistical analysis, encompassing correlation coefficient, mean squared error, Root Mean Squared error, absolute average deviation, absolute average relative deviation, and runtime, confirms the network’s consistent and accurate estimation of system efficiency across various input variables. The study highlights that applying tansig and logsig activation functions, configured with neuron counts of 20, 17, 6 and 23, 20, 2 at the first, second and third hidden layers, respectively, offers enhanced accuracy and reliability. The MLP model’s high performance underscores its potential to identify optimal conditions for H2 generation based on system efficiency, thereby advancing membrane reactor technology for hydrogen production.

Techno economic analysis of electrolytic hydrogen production by alkaline and PEM electrolysers using MCDM methods

Hydrogen, a crucial clean and renewable energy source, addresses pressing challenges of energy security and environmental pollution. Water electrolysis for hydrogen production is a promising approach to satisfy the growing demand for sustainable energy. This study uniquely performs a comprehensive techno-economic analysis of hydrogen production using both Alkaline and Proton Exchange Membrane (PEM) electrolyzers, a first in the field to evaluate their performance comprehensively with advanced Multi-Criteria Decision-Making (MCDM) techniques. Leveraging TOPSIS, WASPAS interval methods, and the Best Worst Method (BWM) with fuzzy logic, this research introduces a novel evaluation framework that incorporates a wide-ranging set of factors, including environmental, technical, technological, economic, and social aspects, divided into 30 sub-criteria. These insights offer a comprehensive understanding of each electrolyser's strengths and weaknesses, helping stakeholders make informed decisions about cost reduction in hydrogen production technologies. This has not been done before. Although cost results favour Alkaline electrolysers, PEM electrolysers are attractive for specific applications where their benefits justify the higher initial cost, choosing between Alkaline and PEM electrolysers dependent on a given hydrogen production project's requirements.

Comparative assessment of the scientific structure of biomass-based hydrogen from a cross-domain perspective

Biomass-based hydrogen production is an innovative approach for realizing carbon-neutral energy solutions. Despite their promise, both structures differ in terms of the biomass energy domain, which is at the entry point of the technology, and the hydrogen energy domain, which is at the exit point of the technology. In this study, we conducted structural and predictive analyses via cross-domain bibliometric analysis to clarify the differences in the structures and perspectives of researchers across domains and to suggest ways to strengthen collaboration to promote innovation. Our study revealed that the hydrogen energy domain has a balanced impact on realizing a hydrogen society using biomass-based hydrogen production technology, while the biomass energy domain has a strong interest in the process of processing biomass. The results reveal that different communities have different ideas about research, resulting in a divide in the areas to be achieved. This comparative analysis reveals the importance of synergistic progress through interdisciplinary efforts. By filling these gaps, our findings can lead to the development of a roadmap for future research and policy development in renewable energy and highlight the importance of a unified approach to sustainable hydrogen production. The contribution of this study is to provide evidence for the importance of cross-disciplinary cooperation for R&D directors and policy makers.

Regulating Ru-O Bond and Oxygen Vacancies of RuO2 by Ta Doping for Electrocatalytic Oxygen Evolution in Acid Media.

Proton exchange membrane water electrolysis (PEMWE) is considered an ideal green hydrogen production technology with promising application prospects. However, the development of efficient and stable acid electroanalytic oxygen electrocatalysts is still a challenging bottleneck. This progress is achieved by adopting a strategic approach with the introduction of the high valence metal Ta to regulate the electronic configuration of RuO2 by manipulating its local microenvironment to optimize the stability and activity of the electrocatalysts. The Ta-RuO2 catalysts are notable for their excellent electrocatalytic activity, as evidenced by an overpotential of only 202 mV at 10 mA cm-2, which significantly exceeds that of homemade RuO2 and commercial RuO2. Furthermore, the Ta-RuO2 catalyst exhibits exceptional stability with negligible potential reduction observed after 50 h of electrolysis. Theoretical calculations show that the asymmetric configuration of Ru-O-Ta breaks the thermodynamic activity limitations usually associated with adsorption evolution, weakening the energy barrier for the formation of the OOH* formation. The strategic approach presented in this study provides an important reference for the development of a stable active center for acid water splitting.