Hydrogen Production Technologies Research Articles

Navigating Alkaline Hydrogen Evolution Reaction Descriptors for Electrocatalyst Design

The quest for efficient green hydrogen production through Alkaline Water Electrolysis (AWE) is a critical aspect of the clean energy transition. The hydrogen evolution reaction (HER) in alkaline media is central to this process, with the performance of electrocatalysts being a determining factor for overall efficiency. Theoretical studies using energy-based descriptors are essential for designing high-performance alkaline HER electrocatalysts. This review summarizes various descriptors, including water adsorption energy, water dissociation barrier, and Gibbs free energy changes of hydrogen and hydroxyl adsorption. Examples of how to apply these descriptors to identify the active site of materials and better design high-performance alkaline HER electrocatalysts are provided, highlighting the previously underappreciated role of hydroxyl adsorption-free energy changes. As research progresses, integrating these descriptors with experimental data will be paramount in advancing AWE technology for sustainable hydrogen production.

Bridging Quantum Mechanics and Hydrogen Technology: The MEQ Framework

The quest for sustainable and renewable energy sources has become a paramount objective in the contemporary scientific and technological landscape. Amidst various alternatives, hydrogen emerges as a promising candidate, offering a clean, efficient, and versatile fuel option. However, the efficient and cost-effective production of hydrogen, particularly through water splitting, presents significant scientific and engineering challenges. This article delves into the innovative convergence of theoretical physics and practical engineering through the lens of the McGinty Equation (MEQ). The MEQ framework, a novel integration of quantum field theory and fractal potentials, proposes groundbreaking approaches to optimize the water-splitting process at the atomic and molecular levels. This exploration is not merely an academic exercise but a step towards tangible solutions in the pursuit of sustainable energy, with the MEQ playing a pivotal role in enhancing hydrogen production technologies.

Technology for Green Hydrogen Production: Desk Analysis

The use of green hydrogen as a high-energy fuel of the future may be an opportunity to balance the unstable energy system, which still relies on renewable energy sources. This work is a comprehensive review of recent advancements in green hydrogen production. This review outlines the current energy consumption trends. It presents the tasks and challenges of the hydrogen economy towards green hydrogen, including production, purification, transportation, storage, and conversion into electricity. This work presents the main types of water electrolyzers: alkaline electrolyzers, proton exchange membrane electrolyzers, solid oxide electrolyzers, and anion exchange membrane electrolyzers. Despite the higher production costs of green hydrogen compared to grey hydrogen, this review suggests that as renewable energy technologies become cheaper and more efficient, the cost of green hydrogen is expected to decrease. The review highlights the need for cost-effective and efficient electrode materials for large-scale applications. It concludes by comparing the operating parameters and cost considerations of the different electrolyzer technologies. It sets targets for 2050 to improve the efficiency, durability, and scalability of electrolyzers. The review underscores the importance of ongoing research and development to address the limitations of current electrolyzer technology and to make green hydrogen production more competitive with fossil fuels.

In-situ construction of N-doped Zn0.6Cd0.4S/oxygen vacancy-rich WO3 Z-scheme heterojunction compound for boosting photocatalytic hydrogen production

Photocatalytic water splitting technology for H2 production represents a promising and sustainable approach to clean energy generation. In this study, a high concentration of oxygen vacancies was introduced into tungsten trioxide (WO3) to create a vacancy-rich layer. This modified WO3 (WO3-x) was then combined with N-doped Zn0.6Cd0.4S through a hydrothermal synthesis, resulting in the formation of a Z-scheme heterojunction composite aimed at enhancing photocatalytic performance. Under visible light, the H2 production activity of the composite reached an impressive 8.52 mmol·g−1 without adding co-catalyst Pt. This corresponds to enhancements of 7.82 and 4.39 times the production yield of pure ZCS and ZCSN, respectively. However, the hydrogen production increased to 21.98 mmol·g−1 when Pt was added as a co-catalyst. Furthermore, an array of characterizations were employed to elucidate the presence of oxygen vacancies and the establishment of the Z-scheme heterojunction. This structural enhancement significantly facilitates the utilization of photo-generated electrons while effectively preventing photo-corrosion of ZCSN, thus improving material stability. Our study provides a new scheme for the incorporation of oxygen-rich vacancy and the construction of Z-scheme heterojunction, demonstrating a synergistic effect that greatly advances photocatalytic performance.

Hydrogen production with a novel coaxial cylindrical electrolyser: A CFD study

This study introduces a unique coaxial cylindrical electrode design for Alkaline Water Electrolysers (AWEs) that is analyzed to show possible enhancements over the traditional stacked plate design. It investigates the performance of the proposed coaxial AWE for enhanced hydrogen production. Through comprehensive computational simulations, key performance indicators, such as current density and hydrogen volume fraction, are analyzed across various operating parameters. The results of this study indicate that the production rate of hydrogen achieves its highest level at a volume percentage of 3.4 %. This rate is significantly influenced by the concentration of the electrolyte, the distance between the cathode and anode rings, and, to a lesser degree, the porosity of the separator. Consequently, the optimized conditions demonstrate a promising increase in current densities, reaching 1000 mA/cm2 at an operating voltage of 2 V, showcasing the potential for developing more efficient and cost-effective AWE systems. This study further contributes valuable insights into the design and operational improvements needed for the advancement of large-scale hydrogen production technologies.

Catalytic and non-catalytic reactions of methane pyrolysis for hydrogen production in screening and electromagnetic levitation reactors using computational fluid dynamics

Molten metal (MM)-based methane (CH4) pyrolysis is a promising technology for clean hydrogen production with a minimal carbon footprint. Electromagnetic levitation (EMLR) and screening reactors (SR) were used to investigate the intrinsic catalytic reaction kinetics of MM-based CH4 pyrolysis. Heterogeneous catalytic reactions in the SR and EMLR occurred on the surfaces of the MM crucible and droplet, respectively. However, a homogenous non-catalytic reaction may occur just above the surface because the CH4 gas is preheated by the high-temperature MM. This study presents three-dimensional (3D) computational fluid dynamics (CFD) model coupled with chemical reactions to assess the extent to which non-catalytic reactions intervene in CH4 pyrolysis in both the SR and EMLR, which is difficult to measure experimentally. The CFD model validated against experimental data revealed that the non-catalytic reaction accounted for 4.0 % of CH4 pyrolysis in the CH4-Ni0.27Bi0.73 SR at 1045 °C, whereas it represented 0.02 % in the CH4-Sn EMLR at 1021 °C. This result highlights that the EMLR is suitable for studying the intrinsic catalytic reaction kinetics of MM-based CH4 pyrolysis because the non-catalytic reaction occurs to a lesser extent.

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.

Life Cycle Assessment of CO2-Based and Conventional Methanol Production Pathways in Thailand

Methanol production through carbon capture and utilization technologies offers promising alternatives to traditional natural-gas-based methods, potentially mitigating climate change impacts and improving resource efficiency. This study evaluates four methanol production pathways: CO2 hydrogenation, tri-reforming of methane, electrochemical CO2 reduction, and co-electrolysis of CO2 and water. The analysis covers 19 scenarios, combining three electricity mixes (100% Thai grid mix, 50% Thai grid mix and 50% renewable energy, and 100% renewable energy) with two hydrogen production technologies (alkaline water electrolysis and grey hydrogen). Environmental life cycle assessment results showed that most pathways perform well when using the 100% renewable energy with co-electrolysis (CE-100%) showing the most substantial reductions across all impact categories as compared conventional methanol production. Electrochemical reduction demonstrated the poorest environmental performance for all scenarios. In Thailand, implementing the CE-100% pathway could potentially yield 12.4 million tonnes of methanol annually from the cement industry’s CO2 emissions, with an estimated value of approximately USD 5.4 billion, while reducing emissions from the industrial processes and product use (IPPU) sector by 75%. The findings provide valuable insights for policymakers, industry stakeholders, and researchers, supporting Thailand’s transition towards sustainable methanol production and broader climate goals.

Underlying Developments in Hydrogen Production Technologies: Economic Aspects and Existent Challenges

Underlying Developments in Hydrogen Production Technologies: Economic Aspects and Existent Challenges

Highly efficient p-p heterojunction Co3S4/NiS2 electrocatalyst for water splitting and electrochemical oxidation of organic molecules

Organic small molecular-assisted water splitting technology is an efficient and promising technology for hydrogen production, which can meet the needs of obtaining hydrogen energy and protecting the environment. Constructing heterojunctions to enhance the interfacial electron transfer and achieve bifunctionality represents a viable strategy for enhancing the performance of electrocatalysts. In this work, the hollow structure Co3S4/NiS2 p-p heterojunction catalyst has been successfully synthesized by one-step hydrothermal method. Only −0.184, 1.64, 1.44 and 1.56 V vs. RHE are required to drive 50 mA cm−2 for hydrogen evolution reaction (HER), oxygen evolution reaction (OER), urea oxidation reaction (UOR), oxygen evolution reaction in lactic acid solution (OER-LA), respectively. For two-electrode electrolytic process, the cell voltages only need 1.72 V, 1.51 V and 1.61 V to drive 50 mA cm−2 in 1 M KOH, 1 M KOH containing 0.5 M urea and 1 M KOH containing 0.5 M lactic acid electrolytes, and it operates continuously at 50 mA cm−2 for 200 h test without significant decay of activity in 1 M KOH containing 0.5 M lactic acid, showing excellent durability. Density functional theory (DFT) calculation reveals that the p-p heterojunction between Co3S4 and NiS2 facilitates the electron redistribution at interfaces, thereby promoting the electron migration. This work presents a strategic approach for fabricating advanced bifunctional electrocatalysts by employing metal sulfides to form heterojunction, thereby achieving enhanced electrocatalytic activities in both hydrogen production and organic molecule decontamination.

Terbium- and samarium-doped Li2ZrO3 perovskite materials as efficient and stable electrocatalysts for alkaline hydrogen evolution reactions

The preparation of highly active, rare earth, non-platinum-based catalysts for hydrogen evolution reactions (HER) in alkaline solutions would be useful in realizing green hydrogen production technology. Perovskite oxides are generally regarded as low-active HER catalysts, owing to their unsuitable hydrogen adsorption and water dissociation. In this article, we report on the synthesis of Li2ZrO3 perovskites substituted with samarium and terbium cations at A-sites for the HER. LSmZrO3 (LSmZO) and LTbZrO3 (LTbZO) perovskite oxides are more affordable materials, starting materials in abundance, environmentally friendly due to reduced usage of precious metal and moreover have potential for several sustainable synthesis methods compared to commercial Pt/C. The surface and elemental composition of the prepared materials have been confirmed by X-ray photoelectron spectroscopy (XPS). The morphology and composition analyses of the LSmZO and LTbZO catalysts showed spherical and regular particles, respectively. The electrochemical measurements were used to study the catalytic performance of the prepared catalyst for hydrogen evolution reactions in an alkaline solution. LTbZO generated 2.52 mmol/g/h hydrogen, whereas LSmZO produced 3.34 mmol/g/h hydrogen using chronoamperometry. This was supported by the fact that the HER electrocatalysts exhibited a Tafel slope of less than 120 mV/dec in a 1.0 M alkaline solution. A current density of 10 mA/cm2 is achieved at a potential of less than 505 mV. The hydrogen production rate of LTbZO was only 58.55%, whereas LSmZO had a higher Faradaic efficiency of 97.65%. The EIS results demonstrated that HER was highly beneficial to both electrocatalysts due to the relatively small charge transfer resistance and higher capacitance values.

Degradation behavior of galvanostatic and galvanodynamic cells for hydrogen production from high temperature electrolysis of water

High temperature electrolysis of water using solid oxide electrochemical cells (SOEC) is a promising technology for hydrogen production with high energy efficiency and may promote decarbonization when coupled with renewable energy sources and excess heat from nuclear reactors. Apart from the technoeconomic considerations, commercial deployment of this technology critically depends on the long-term performance and durability of SOEC cells/stacks, especially under dynamic operations to withstand the intermittency of renewable energy. Herein, SOEC operation was conducted under galvanodynamic conditions and compared with galvanostatic cells to examine the effect on degradation behavior at an average current density of −0.75 A cm−2 at 750 °C. While dynamic operation shows no significant impact on the overall degradation rates compared to constant current operation, minor performance improvement was observed at potentials above 1.5 V when switched to galvanodynamic mode. The relatively lower overpotential during dynamic operation could not be explained by the negligible changes in the electrochemical impedance or cell temperature. Multiphysics modeling reveals that the oxygen partial pressure (PO2) in the electrolyte oscillates with the alternating current density under dynamic operations. The minor improvement in cell performance under dynamic mode might be associated with the relatively lower PO2 buildup as compared with that under galvanostatic operation. In addition, dynamic operation at high frequencies could effectively lower the extreme PO2 in the electrolyte, thus relieving stresses in the cells and alleviating cell degradation.

Assessing the impact of hydrogen trade towards low-carbon energy transition

Hydrogen is increasingly recognized as a pivotal commodity in the low-carbon energy transition, bridging regional disparities in hydrogen production capacity and facilitating international energy trade. Existing research has yet to delve into the impact of global hydrogen trade on energy transitions, as well as the key factors driving the development of hydrogen trade. This study, utilizing the updated GCAM-TU model, which mainly extends the original Global Change Analysis Model (GCAM) with a hydrogen trade module, provides a multi-scenario outlook on the characteristics of hydrogen trade and its impact on global and regional energy transition. The findings indicate that by 2050, the global hydrogen trade volume is expected to reach 9-19EJ, accounting for a quarter of the global hydrogen consumption in different scenarios, with green hydrogen trade dominating due to its cost advantages. Pipeline hydrogen and ammonia shipping will govern the trade market, representing 33%–61% and 24%–64% of trade volume, respectively, while liquid hydrogen shipping holds an advantage for medium distances. Hydrogen trade is projected to increase global hydrogen demand by 1.2–5.3EJ and reduce hydrogen prices by 11%–36% in the European Union, Japan, and South Korea, thereby expanding their hydrogen consumption by 8%–55% and reducing regional carbon prices by 1%–6%. Moreover, hydrogen trade significantly alters the regional distribution of global hydrogen production, with major exporting regions such as North and East Africa increasing their hydrogen production for export by up to 150%. To facilitate the development of hydrogen and hydrogen trade, it is crucial for potential importing and exporting regions to enhance global financial and technological cooperation, develop key hydrogen production and transportation technologies, and retrofit existing nature gas infrastructure to reduce costs. Additionally, forming stable trade partnerships is essential for maintaining energy security in the hydrogen trade.

Prospective Life Cycle Assessment of Hydrogen: A Systematic Review of Methodological Choices

This systematic review examines methodological choices in assessing hydrogen production and utilisation technologies using prospective life cycle assessments (LCA) between 2010 and 2022, following PRISMA guidelines. The review analysed 32 peer-reviewed articles identified through Scopus, Web of Science, and BASE. The study reveals a significant gap in the consistent application of prospective LCA methodologies for emerging hydrogen technologies. Most studies employed attributional approaches, often lacking prospective elements in life cycle inventory (LCI) modelling. Although some initiatives to integrate forward-looking components were noted, there was often lack of clarity in defining LCA objectives, technology readiness level (TRL), and upscaling methods. Of the 22 studies that focused on emerging hydrogen technologies, few detailed upscaling methods. Additionally, the review identified common issues, such as the limited use of prospective life cycle impact assessment (LCIA) methods, inadequate data quality evaluation, and insufficient sensitivity and uncertainty analysis. These findings highlight the substantial gaps in modelling low-TRL hydrogen technologies and the need for more robust, comprehensive approaches to assess uncertainties. The review also identified common practices and areas for improvement to enhance the reliability and relevance of hydrogen technology environmental assessments.

Strong electron coupling effect of non-precious metal Schottky junctions enhanced square meter level photocatalytic hydrogen evolution

Photocatalytic hydrogen production technology utilizes solar energy to decompose water into hydrogen, helping to alleviate the pressure of energy depletion. Engineering of non-precious metal nanomaterials as cocatalysts can play a significant role in low-cost, sustainable, and large-scale photocatalytic hydrogen production. Herein, MnCdS-Vs/NiCo2S4 (MCSN) Schottky junction nanomaterials with strong electron coupling effect were prepared by a two-step hydrothermal method and successfully applied to a square meter hydrogen evolution device. The optimized MCSN material demonstrated high hydrogen evolution activity of 34.28 mmol g−1 h−1, which is 9.34 and 685.60 times higher than that of pure MnCdS-Vs and NiCo2S4, respectively. More importantly, in a square meter (1 m2) flat-plate reactor, MCSN produced H2 evolution approximately 201 mmol in 5 h, showcasing its potential for large-scale applications. In-situ XPS and DFT calculations demonstrated that MnCdS-Vs interacts with NiCo2S4 to produce a strong electron coupling effect and form a Schottky junction. It promotes the facilitated the directional migration of photogenerated electrons from MnCdS-Vs to NiCo2S4, but also effectively suppressed electron backflow through the Schottky barrier. Furthermore, the abundance of sulfur vacancies enhanced visible light absorption capability, further improving photocatalytic hydrogen evolution performance. This work delves into the role of defect engineering and Schottky junction design in enhancing photocatalytic performance, providing new insights into transitioning photocatalytic hydrogen production technologies from small-scale laboratory experiments to large-scale practical applications.

Knowledge Graph of Low-Carbon Technologies in the Energy Sector and Cost Evolution Based on LDA2Vec: A Case Study in China

Climate change has attracted global attention, highlighting the critical role of low-carbon technologies in addressing environmental challenges. Due to the multidisciplinary nature, complexity, and diversity of research content on low-carbon technologies, a comprehensive overview is still limited. This paper uses bibliometrics analysis to discuss the research status and hotspots of low-carbon technology from a macro-perspective. The LDA2Vec topic recognition model is adopted to identify key technical terms, and CiteSpace software 6.3.1 Advanced Edition is used to conduct in-depth analysis of the development trajectory of low-carbon technology. After checking the frequency of the relevant keywords, four key techniques were identified. In order to further analyze the research results, the learning curve theory is used to predict the cost development trend of key low-carbon technologies. The results show that: (i) low-carbon technologies play a key role in the energy sector and have a potential impact on policy making, and the cost of related technologies will be significantly reduced in the next few years. (ii) Global low-carbon technologies have entered an important period of development, but remaining challenges need to be addressed by optimizing technological performance. (iii) It is very important to strengthen the research on hydrogen production technology and photovoltaic power generation technology; the cost reduction in hydrogen production technology is still significant and there is room for further optimization. (iv) To effectively address the high costs and technical barriers associated with emerging low-carbon technologies, increased funding for research and development is critical.

Controlled synthesis of Sn doped Cu–Ni3S2 on Ni foam as efficient electrocatalyst for urea oxidation reaction and oxygen evolution reaction

Hydrogen production technology by urea-assisted electrocatalytic water decomposition has become one of the important means to alleviate carbon emissions and water pollution. In this paper, we first doped Sn and Cu element into the Ni3S2 material by hydrothermal method on the Ni foam support. This Cu–Sn–Ni3S2 material exhibits superior urea (potential of 1.42 V at 100 mA cm−2) and water oxidation (potential of 1.63 V at 100 mA cm−2) properties, which is one of the best electrochemical performance reported up to now. Analysis of experiment demonstrate that the increase in catalytic performance is assigned to faster charge transfer, more exposure of reaction centres and smaller resistance owing to doping of Sn and Cu. Density functional theory (DFT) analysis demonstrates that introduction of Sn and Cu increases the adsorption energy of urea and improves the conductivity of the Cu–Sn–Ni3S2 material, and the co-doping of the two changes the electron state density of the active site, thereby promoting the catalytic performance. This work provides insights into the development of efficient bifunctional electrodes for urea oxidation and oxygen evolution reaction through doping strategies.

Advances in green hydrogen generation based on MoSe2 hybrid catalysts

Green hydrogen production technology is of great significance in realizing energy transition and combating climate change. Recently, with the rapid development of nanomaterials and catalytic technology, transition metal dichalcogenides represented by MoSe2 have attracted wide attention in the field of hydrogen production. This review comprehensively reviewed the applications and recent progress of MoSe2 in green hydrogen production in terms of photocatalytic water splitting for hydrogen production, water electrolysis and methanol-assisted water electrolysis for hydrogen production. The active site and electronic structure-related optimization of MoSe2 was also carried out through various optimization strategies to improve its green hydrogen production efficiency. The challenges and perspectives of MoSe2 hybrid catalysts were also concluded. This review showed a comprehensive overview of MoSe2 hybrid catalysts by summarizing the optimization strategies for catalyst property modification and their application in hydrogen production, which would be helpful for relevant progress understanding.

High Temperature Solid Oxide Electrolysis for Green Hydrogen Production.

Global warming and energy crises have motivated the development of renewable energy and its energy carriers. Green hydrogen is the most promising renewable energy carrier and will be fundamental to future energy conversion and storage systems. Solid Oxide Electrolysis Cells (SOECs) are a promising green hydrogen production technology featuring high electrical efficiency, no noble metal catalyst usage, and reversible operation. This review provides a timely summary of the latest SOEC progress, covering developments at various levels, from cells to stacks to systems. Cell/stack components, configurations, advanced electrode material/fabrication, and novel characterization methods are discussed. Electrochemical and durable performance for each cell/stack configuration is reviewed, focusing on degradation mechanisms and associated mitigation strategies. SOEC system integration with renewable energy and downstream users is outlined, showing flexibility, robustness, scalability, viability, and energy efficiency. Challenges of cost and durability are expected to be overcome by innovation in material, fabrication, production, integration, and operation. Overall, this comprehensive review identifies the SOEC commercialization bottleneck, encourages further technology development, and envisions a future green hydrogen society with net-zero carbon emissions.

Integrating green hydrogen production with renewable energy-powered desalination: An analysis of CAPEX implications and operational strategies

The study examines how sustainable energy transitions can meet freshwater needs in green hydrogen production. It proposes four configurations that combine polymer electrolyte membrane (PEM) water electrolysis with renewable energy-powered desalination methods, capable of both continuous and intermittent operations. This study evaluates the capital expenditure (CAPEX) implications of integrating solar or wind energy with seawater reverse osmosis (SWRO) and multi-effect distillation (MED) desalination to produce green hydrogen. It examines the capacities of renewable energy sources, the effectiveness of energy storage solutions, and the performance of various desalination methods, particularly their combined impact on economic viability and overall project costs. An SWRO system intermittently powered by wind energy is identified as the most cost-effective, reducing CAPEX by 46%. The results emphasize the practical benefits of integrating green desalination with green hydrogen production technologies.