Table of Contents
Overview
Properties of Hydrogen
Hydrogen possesses several unique properties that make it a compelling alternative to traditional fossil fuels. Its environmentally benign nature and high mass energy density contribute to its appeal as a clean energy carrier, positioning it as a viable substitute for fossil fuels in both mobile and fixed applications.[22.1] Hydrogen can be produced through various methods, including water electrolysis, steam methane reforming, methane pyrolysis, and coal gasification, each with differing environmental impacts.[23.1] Currently, approximately 95% of global hydrogen production is derived from fossil fuels, resulting in significant carbon dioxide emissions, totaling around 830 million tonnes annually for 74 million tonnes of hydrogen produced.[21.1] In contrast, green hydrogen, produced through renewable methods, generates zero greenhouse gas emissions, making it a more sustainable option.[20.1] As global demand for hydrogen is projected to rise from 70 million tonnes in 2019 to 120 million tonnes by 2024, it is essential to critically assess the environmental impacts of various production routes and explore options for seasonal storage and utilization.[23.1] This assessment is crucial for ensuring the long-term viability of clean and green hydrogen as a key player in the transition to a low-carbon economy.[2.1]In this section:
History
Early Discoveries
The informal discovery of hydrogen can be traced back to the 1500s when the alchemist Paracelsus observed the production of bubbles, which we now recognize as gas, when sulfuric acid was added to iron. This observation was later echoed by Robert Boyle in 1671, who also noted the production of flammable bubbles during his experiments with metals and acids.[46.1] However, the formal identification of hydrogen as a distinct element is credited to Henry Cavendish, who, in 1766, isolated hydrogen gas while investigating the composition of water and the nature of gases.[64.1] Cavendish's work was pivotal; he described hydrogen as "inflammable air" and demonstrated its properties, including its ability to form water upon combustion, in a paper titled "On Factitious Airs".[45.1] His experiments included reacting zinc with hydrochloric acid, which produced hydrogen gas, and he famously applied a spark to this gas, yielding water, thereby providing evidence that water is composed of hydrogen and oxygen.[64.1] Although Cavendish is often credited with the discovery of hydrogen, it was Antoine Lavoisier who, in 1783, named the element "hydrogen," derived from the Greek words for "water" and "creator," after he successfully reproduced Cavendish's findings.[61.1] This naming marked a significant milestone in the scientific understanding of hydrogen, as it helped to solidify its status as a fundamental element in chemistry. These early discoveries not only advanced the field of chemistry but also challenged existing theories, such as the Aristotelian concept of the four elements, by demonstrating that water and air were not the only basic substances.[61.1] The cumulative work of these early scientists laid the groundwork for future research and applications of hydrogen, establishing its importance in both scientific inquiry and practical applications.Recognition as an Element
Hydrogen's recognition as a distinct chemical element emerged from its unique reactivity and the significant chemical reactions it participates in. One of the earliest demonstrations of hydrogen's properties was its production through the reaction of metals with acids, such as zinc reacting with hydrochloric acid to yield hydrogen gas and zinc chloride.[47.1] This reaction exemplifies hydrogen's role in various chemical processes and its ability to form compounds with other elements. Further exploration of hydrogen's reactivity revealed its interactions with group 1 metals and alkaline earth metals like strontium, barium, and calcium when heated. These reactions typically produce acidic hydrogen molecules, indicating hydrogen's capacity to exist in different oxidation states, particularly the 1+ state when reacting with nonmetals.[48.1] As the electronegativity of the nonmetals increases, these reactions become more volatile and exothermic, highlighting the dynamic nature of hydrogen's chemical behavior. A pivotal moment in the history of hydrogen was its reaction with oxygen, which occurs under specific conditions, such as ignition by a flame or spark. This reaction can lead to a fire or explosion, producing water as the sole product, represented by the equation 2 H₂ (g) + O₂ (g) → 2 H₂O (g).[50.1] The characteristic reddish flame observed during this reaction further underscores hydrogen's energetic properties and its significance in chemical studies. Additionally, hydrogen's ability to react with nitrogen in the Haber process marks another critical development in its recognition as an element. This process is essential for synthesizing ammonia, which has profound implications for agriculture and industry.[49.1] The formation of ionic hydrides, which contain the hydride anion (H⁻), also illustrates hydrogen's role as a strong reducing agent and base, capable of vigorous reactions with water and acids to produce hydrogen gas.[51.1]Recent Advancements
Hydrogen Production Technologies
Recent advancements in hydrogen production technologies have focused on improving the efficiency and sustainability of various electrolysis methods. Alkaline water electrolysis (A-WE), proton exchange membrane (PEM) electrolysis, and anion exchange membrane (AEM) electrolysis are among the prominent techniques being explored. A-WE operates at temperatures between 30-90 °C and utilizes nickel electrodes, achieving energy efficiencies ranging from 62% to 82%.[99.1] Recent innovations in this area include the integration of solar energy with A-WE, which has led to the development of low-cost electrolyzers that enhance hydrogen production rates and energy efficiency.[96.1] In addition to A-WE, steam electrolysis has seen significant advancements, particularly with the introduction of straight pore diffusion channels that improve the process's thermal energy management.[97.1] This method, while requiring thermal energy for water evaporation, is being optimized to enhance its overall efficiency for green hydrogen production. The research community is also actively investigating chemical-assisted water electrolysis systems, which aim to improve energy efficiency through innovative catalyst design strategies. This approach promises to deliver enhanced performance in hydrogen production, particularly in terms of low-voltage operation and long-term stability.[98.1] Furthermore, the integration of renewable energy sources such as wind, solar, and geothermal with electrolysis technologies is crucial for the sustainability of hydrogen production. These renewable sources not only reduce greenhouse gas emissions but also decrease reliance on fossil fuels, thereby contributing to a cleaner energy transition.[122.1] However, challenges remain in achieving high efficiency and cost-effectiveness at scale, necessitating ongoing research and development.[119.1]Innovations in Hydrogen Applications
Recent advancements in hydrogen applications have focused on enhancing production, storage, and utilization technologies, positioning hydrogen as a pivotal player in the transition to sustainable energy systems. Hydrogen is recognized as the most environmentally friendly and cleanest fuel, with the potential to replace fossil fuels and address global energy shortages, particularly in complex geographic regions.[91.1] Innovations in hydrogen production have primarily centered around electrolysis and steam methane reforming (SMR). Electrolysis, which splits water into hydrogen and oxygen using electricity, becomes significantly more impactful when powered by renewable energy sources such as solar, wind, and hydroelectric power, resulting in the production of green hydrogen that is entirely carbon-free.[94.1] Despite the current reliance on fossil fuels for approximately 96% of global hydrogen production, advancements in electrolysis and other renewable methods are crucial for achieving a sustainable energy transition.[95.1] In terms of hydrogen storage, recent developments have explored a variety of advanced materials and technologies. Solid-state hydrogen storage using reticular materials, such as metal-organic frameworks (MOFs), has emerged as a promising alternative, allowing for hydrogen storage at low pressures and ambient temperatures without compromising capacity.[104.1] MOFs are particularly notable due to their ultrahigh surface area and rapid kinetics for hydrogen adsorption and desorption, making them highly efficient candidates for hydrogen storage.[105.1] Other materials under investigation include covalent organic frameworks (COFs), metal-doped frameworks, and complex chemical hydrides, which offer significant storage capacities and reliable cycle stability.[107.1] The Hydrogen and Fuel Cell Technologies Office (HFTO) has been instrumental in advancing research and development in hydrogen and fuel cell technologies, focusing on diverse applications that contribute to energy independence and security.[93.1] The integration of these technologies into transportation and other sectors is essential for fostering a robust hydrogen economy.In this section:
Occurrence And Abundance
Hydrogen in the Universe
Hydrogen is the most abundant element in the universe, constituting approximately 92% of the total number of atoms and about 75% of the universe's mass. Helium follows as the second most abundant element, making up roughly 23% of the mass, while all other elements combined account for only about 2% of the universe's composition.[139.1] This abundance is primarily a result of Big Bang nucleosynthesis, during which hydrogen and helium were formed in large quantities shortly after the universe's inception.[138.1] The significance of hydrogen extends beyond mere abundance; it plays a crucial role in the formation of stars and galaxies. The immense gravitational pressure within stellar cores facilitates the fusion of hydrogen atoms into helium, a process known as nuclear fusion, which is fundamental to stellar evolution.[142.1] The presence of atomic hydrogen is essential for star formation, as it serves as a key ingredient in the cosmic recipe for creating new stars.[145.1] Furthermore, the formation of molecular hydrogen is considered a critical step in the cooling process that allowed the first stars to assemble in the early universe.[146.1] In the context of cosmic evolution, the abundance of hydrogen has profound implications. The first generation of stars, composed solely of hydrogen and helium, significantly altered the chemical and thermal state of the surrounding gas, thereby triggering the formation of the first galaxies and initiating a self-sustaining cycle of star formation and chemical enrichment.[149.1] Additionally, intense ultraviolet radiation from these early stars likely contributed to the reionization of intergalactic hydrogen, marking a pivotal event in cosmic history.[148.1]Position In The Periodic Table
Atomic Structure
Hydrogen is the first element in the periodic table, characterized by its atomic number one, which indicates that it has only one electron in its outermost shell.[210.1] This unique atomic structure, with an electronic configuration of (1s^1), positions hydrogen at the top of group 1, where it is often grouped with alkali metals due to its similar outer electron configuration.[211.1] However, hydrogen's properties exhibit dual characteristics; it behaves like alkali metals when it loses its single electron to form a cation (H⁺) but resembles halogens when it gains an electron to form a uni-negative ion.[209.1] The placement of hydrogen in the periodic table has been a subject of debate among chemists, as its behavior does not align perfectly with either alkali metals or halogens. While it shares some chemical properties with alkali metals, such as forming oxides, halides, and sulfides, it possesses a significantly higher ionization enthalpy, which results in a lack of metallic characteristics under standard conditions.[209.1] This complexity leads to the conclusion that hydrogen's position is not fixed, as it can be seen as a member of both groups depending on the context of its chemical behavior.[215.1] Historically, the classification of hydrogen has evolved through various scientific discoveries. The early identification of hydrogen as a distinct element by Henry Cavendish in 1766 marked a pivotal moment in chemistry, leading to further exploration of its properties and behaviors.[214.1] Over time, different versions of the periodic table have attempted to accommodate hydrogen's unique characteristics, sometimes placing it at the top of group 1 or group 7, reflecting the ongoing discussion regarding its classification.[215.1]Chemical Behavior
Hydrogen exhibits unique chemical behavior that reflects its position in the periodic table, particularly in relation to alkali metals and halogens. As the first element, hydrogen has an atomic number of 1 and an electronic configuration of 1s¹, which is similar to the outer electronic configuration of alkali metals in Group 1 (ns¹).[194.1] This similarity allows hydrogen to form compounds with an oxidation state of +1, resembling the behavior of alkali metals.[190.1] However, hydrogen can also gain an electron to form a hydride ion (H⁻), which aligns it with the halogens that typically have an oxidation state of -1.[196.1] The ability of hydrogen to form both cations (H⁺) and anions (H⁻) significantly influences its reactivity. When hydrogen is oxidized by more electronegative elements, it forms compounds with a +1 oxidation state, while it can be reduced by less electronegative elements to achieve a -1 oxidation state.[186.1] This dual capability complicates its classification, as it shares properties with both alkali metals and halogens.[195.1] Despite these similarities, hydrogen's chemical behavior diverges from that of alkali metals and halogens in several respects. For instance, hydrogen has a much higher ionization energy compared to alkali metals, which limits its metallic characteristics under normal conditions.[193.1] Additionally, while hydrogen can participate in ionic and covalent bonding, its reactivity is generally lower than that of halogens.[195.1]Applications Of Hydrogen
Industrial Uses
Hydrogen plays a crucial role in various industrial applications, significantly impacting sectors such as food processing, petrochemicals, and fertilizers. In the food industry, hydrogen is utilized to increase the saturation level of fats and oils, particularly in vegetable cooking oils, due to its ability to break down fats effectively.[230.1] Additionally, hydrogen is a key component in the production of food acids and bases, further underscoring its importance in food manufacturing.[230.1] In the petroleum industry, hydrogen is extensively used to remove sulfur content from fuels, enhancing the quality of petroleum products.[229.1] It also serves as a shielding gas in welding processes, where it generates heat and protects the weld from oxidation.[229.1] The versatility of hydrogen extends to its use in the production of ammonia through the Haber-Bosch process, which combines hydrogen and nitrogen under specific conditions to create ammonia, a vital ingredient in fertilizers.[232.1] This process is essential for global food production, as ammonia is a critical component of fertilizers used to support agricultural yields.[232.1] Moreover, hydrogen is involved in the production of hydrogen peroxide, which traditionally requires a multi-step process but has seen advancements allowing for on-demand production from hydrogen and oxygen.[231.1] The industrial applications of hydrogen are further complemented by safety services provided by organizations like WHA International, which focus on ensuring safe practices in the growing hydrogen industry.[233.1] Overall, the utilization of hydrogen in these various sectors highlights its significance as a versatile and essential industrial gas.Emerging Technologies
The integration of hydrogen into various applications is paving the way for emerging technologies that promise to enhance sustainability and efficiency across multiple sectors. One significant area of focus is the use of hydrogen in energy systems, where it serves as a crucial component for stabilizing intermittent renewable energy sources and providing long-term energy storage solutions. However, the effective incorporation of hydrogen into existing electricity infrastructure necessitates substantial modifications and improvements to current systems.[242.1] Moreover, hydrogen's potential as a sustainable energy vector is underscored by its role in the Haber-Bosch process for ammonia production. Traditionally, ammonia has been produced through carbon-intensive methods, contributing significantly to global CO2 emissions. The integration of green hydrogen into this process can lead to a more sustainable ammonia synthesis, thereby reducing the carbon footprint associated with fertilizer production, which is vital for global food security.[248.1] Advancements in electro-catalytic processes for ammonia synthesis further enhance this potential by enabling production with zero carbon emissions, thus promoting a pollution-free approach to meeting the chemical industry's demands.[247.1] In the realm of propulsion systems, liquid hydrogen is emerging as a superior alternative to traditional rocket fuels. Nuclear Thermal Propulsion (NTP) systems utilize liquid hydrogen to generate thrust through a nuclear reactor, achieving higher efficiency compared to conventional chemical propulsion methods.[249.1] This shift not only improves performance but also reduces the environmental impact associated with rocket launches, aligning with broader sustainability goals.[251.1]Environmental Impact
Hydrogen as a Clean Energy Source
Hydrogen is increasingly recognized as a clean energy source, particularly when produced through renewable methods. The predominant method of hydrogen production today is steam methane reforming (SMR) of natural gas, which, while effective, results in significant greenhouse gas emissions, thus raising environmental concerns.[283.1] In contrast, hydrogen generated from renewable energy sources, such as solar or wind power, is considered environmentally friendly and is essential for achieving climate-neutrality targets by 2050.[275.1] The environmental impact of hydrogen production varies significantly depending on the method employed. For instance, hydrogen production via fossil fuels, particularly through SMR, has been shown to have the highest environmental impacts in terms of abiotic depletion and global warming potential.[283.1] Conversely, hydrogen produced from renewable resources, often referred to as green hydrogen, offers substantial environmental benefits, including zero carbon emissions during its use.[279.1] This clean-burning characteristic positions hydrogen as a leading candidate for sustainable energy solutions, especially as it produces only water vapor as a byproduct.[279.1] Moreover, the transition to hydrogen power plants can lead to enhanced energy independence, as hydrogen can be produced from a variety of local resources, unlike fossil fuels, which are geographically concentrated.[280.1] This versatility not only supports energy security but also aligns with global sustainability goals.[285.1] However, to fully realize the environmental benefits of hydrogen, it is crucial to ensure that production methods are sustainable and economically viable.[284.1]Challenges and Barriers to Adoption
The integration of hydrogen as a clean energy source is hindered by several critical challenges that need to be addressed to enable its widespread adoption. A major barrier is the high cost of producing green hydrogen, which is primarily due to the reliance on expensive water electrolysis processes. Currently, only 4% of global hydrogen production comes from this method, while the majority is derived from fossil fuels, resulting in significant emissions. This underscores the necessity for technological advancements to reduce production costs and improve sustainability.[307.1] Another significant challenge is the underdeveloped infrastructure for hydrogen distribution. The storage and transportation of hydrogen require substantial improvements in logistics and technology to establish an efficient and clean hydrogen value chain.[305.1] Additionally, regulatory uncertainties and the slow pace of implementing supportive policies in key regions like the European Union and the United States further impede the growth of the hydrogen sector. A well-defined policy strategy is crucial to attract investment and guide the market towards viable hydrogen applications.[308.1] To address these challenges, it is essential for policymakers to create comprehensive frameworks that support the research, development, and commercialization of hydrogen technologies. This involves fostering technological innovation, promoting economic development, and engaging with diverse communities to build an enabling environment for hydrogen energy.[306.1] Collaborative efforts among government, industry, academia, and civil society are vital to unlocking the full potential of hydrogen as a clean, reliable, and sustainable energy source.[299.1]References
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[20] The Impact of Hydrogen on the Environment: Production, Transportation ... — In conclusion, green hydrogen has a minimal environmental impact compared to other hydrogen or traditional fossil fuels. Its production, transportation, and use produce zero greenhouse gas emissions, making it an attractive alternative for a sustainable future. While grey and blue hydrogen have some environmental impacts, they are still cleaner
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[22] Essential parts of hydrogen economy: Hydrogen production, storage ... — Essential parts of hydrogen economy: Hydrogen production, storage, transportation and application - ScienceDirect Essential parts of hydrogen economy: Hydrogen production, storage, transportation and application The unique features, including its environmentally benign nature, high mass energy density, and known as a clean energy carrier, make hydrogen energy an appealing substitute for fossil fuels in both mobile and fixed applications. This overview presents effective methods for hydrogen synthesis, storage, safe transportation, and application.Technologies for producing hydrogen are already commercially accessible, and some of them are still in development. Compared to the energy derived from fossil fuels, H2 is more challenging for transportation and storage. H. Zhang et al. Hydrogen production for energy: an overview H. Zhang et al.
[23] Hydrogen production, storage, utilisation and environmental impacts: a ... — The global hydrogen demand is projected to increase from 70 million tonnes in 2019 to 120 million tonnes by 2024. Hydrogen is produced by water electrolysis, steam methane reforming, methane pyrolysis and coal gasification. Hydrogen is used in power systems, transportation, hydrocarbon and ammonia production, and metallugical industries. Conclusion To ensure the long-term production of clean and green hydrogen, it is crucial to conduct a critical assessment of various production routes and their environmental impacts, as well as seasonal storage and utilisation options.
[45] 2.1: Discovery of Hydrogen - Chemistry LibreTexts — As a consequence of his work he is usually given credit for its discovery as an element. However, it was Antoine Lavoisier (Figure \(\PageIndex{2}\).4) who in 1783 named the element hydrogen (from the Greek hydro meaning water and genes meaning creator) after he reproduced Cavendish's findings.
[46] The History and Uses of Hydrogen - Let's Talk Science — Hydrogen was first discovered in 1671 by British scientist Robert Boyle. He had been experimenting with different metals by dipping them in acid. When a pure metal is placed in acid, a type of reaction called a single-displacement reaction takes place. For example, adding a piece of potassium (K) to a solution of hydrochloric acid (HCl) causes
[47] Exploring Hydrogen's Role in Chemical Reactions | SCIENCE GEEKS — Chemical Reactions Involving hydrogen . Metal and Acid Reaction (Hydrogen Gas Production): When a metal reacts with an acid, it produces hydrogen gas. Example: Zinc reacts with hydrochloric acid to form hydrogen gas and zinc chloride: Reaction of Water with Active Metals: Active metals like sodium or potassium react with water to produce
[48] Chemical Reactions of Hydrogen - Unacademy — Reactions of Hydrogen with Elements. Hydrogen reacts with group 1 metals and Sr, Ba, and Ca when it is heated. In general, hydrogen reactions with nonmetals result in acidic hydrogen molecules containing hydrogen in a state of 1+ oxidation. As electronegativity of nonmetals grows, the reactions convert to highly volatile and exothermic.
[49] Hydrogen: Chemical reactions - Pilgaard Elements — Hydrogen, H 2, does react with oxygen, O 2, unless ignited with a flame or a spark (and the mixture is the right ratio). The reaction is a fire or explosion, depending on the conditions, with a characteristic reddish flame. 2 H 2 (g) + O 2 (g) 2 H 2 O (g) Nitrogen can be brought to react with hydrogen. This is called the Haber process : N 2
[50] WebElements Periodic Table » Hydrogen » reactions of elements — Reaction of hydrogen with air. Hydrogen is a colourless gas, H 2, that is lighter than air.Mixtures of hydrogen gas and air do not react unless ignited with a flame or spark, in which case the result is a fire or explosion with a characteristic reddish flame whose only products are water, H 2 O.. 2H 2 (g) + O 2 (g) → 2H 2 O(l). Reaction of hydrogen with water
[51] 125 20.5 Occurrence, Preparation, and Compounds of Hydrogen — The compounds formed are crystalline, ionic hydrides that contain the hydride anion, H −, a strong reducing agent and a strong base, which reacts vigorously with water and other acids to form hydrogen gas. The reactions of hydrogen with nonmetals generally produce acidic hydrogen compounds with hydrogen in the 1+ oxidation state. The
[61] 2.1: Discovery of Hydrogen - Chemistry LibreTexts — This was a key experiment in disproving the Aristotelian theory of the four elements. As a consequence of his work he is usually given credit for its discovery as an element. However, it was Antoine Lavoisier (Figure \(\PageIndex{2}\).4) who in 1783 named the element hydrogen (from the Greek hydro meaning water and genes meaning creator) after
[64] History of Hydrogen Timeline - Metropolitan Washington Council of ... — 1766 - Hydrogen was first identified as a distinct element by British scientist Henry Cavendish after he separated hydrogen gas by reacting zinc metal with hydrochloric acid. In a demonstration to the Royal Society of London, Cavendish applied a spark to hydrogen gas yielding water. This discovery led to his later finding that water (H 2 O) is made
[91] The current status of hydrogen energy: an overview - RSC Advances (RSC ... — Hydrogen is the most environmentally friendly and cleanest fuel that has the potential to supply most of the world's energy in the future, replacing the present fossil fuel-based energy infrastructure. Hydrogen is expected to solve the problem of energy shortages in the near future, especially in complex geographic Advances in Sustainable Hydrogen Energy 2023 Reviews in RSC Advances
[93] PDF — PROGRESS IN Hydrogen and Fuel Cells The Hydrogen and Fuel Cell Technologies Office (HFTO) focuses on research & development (R&D) and demonstration activities to advance hydrogen and fuel cell technologies for transportation and diverse applications that contribute to U.S. energy independence, security and resiliency, and add to a strong domestic economy. System FUEL CELL R&D HYDROGEN R&D Cost values incorporate different assumptions of volume production, economies of scale, and technology pathways. Fuel Cell Performance & Durability Advanced H2 Storage Materials PGM-Free Catalysts for Fuel Cells HYDROGEN AND FUEL CELL TECHNOLOGIES OFFICE For more information, visit: hydrogenandfuelcells.energy.gov DOE/EE-1647 • June 2020 2 Renewable H2 Production H2 Materials Compatibility
[94] Hydrogen as a clean energy carrier: advancements, challenges, and its ... — Electrolysis, which splits water using electricity, and SMR are the two most used processes for creating hydrogen. It becomes much more important when electrolysis—a procedure that splits water into hydrogen and oxygen using electricity—is powered by renewable energy sources like solar, wind, and hydroelectric power [].This process yields green hydrogen, which is entirely carbon-free and
[95] Hydrogen as an alternative fuel: A comprehensive review of challenges ... — Hydrogen as an alternative fuel: A comprehensive review of challenges and opportunities in production, storage, and transportation - ScienceDirect Hydrogen as an alternative fuel: A comprehensive review of challenges and opportunities in production, storage, and transportation Evaluated opportunities in hydrogen production, storage, and transport systems. At present, approximately 96% of global hydrogen production relies on fossil fuels, contributing to substantial emissions, while only 4% comes from water electrolysis. This review evaluates hydrogen's potential as a sustainable energy carrier, providing insights into advancements and ongoing challenges in production, storage, and transportation. Key findings highlight the necessity of coordinated efforts to enhance storage technologies, lower production costs, and establish supportive policies, highlighting hydrogen's critical role in achieving a sustainable energy transition. For all open access content, the Creative Commons licensing terms apply.
[96] A comprehensive review of recent advances in alkaline water ... — This review provides a comprehensive overview of recent advances in alkaline water electrolysis (A-WE) for hydrogen production, including a comparative assessment of the four commonly used electrolysis technologies. Hydrogen production by a low-cost electrolyzer developed through the combination of alkaline water electrolysis and solar energy use Upgrading hydrogen production rate and energy efficiency of alkaline water electrolysis under effect of magnetic field First, we explored the current mainstream hydrogen preparation paths, including but not limited to hydroelectrolysis (decomposition of water molecules using renewable energy power); gas steam reforming (traditional but efficient hydrogen production methods requiring carbon emission management); biomass gasification and coal gasification (based on innovative utilisation of renewable and fossil resources); and hydrolysis hydrogen production (advanced cutting-edge technology directly using solar energy).
[97] Advances in steam electrolysis for green hydrogen production: Current ... — Advances in steam electrolysis for green hydrogen production: Current status and future outlook ... ]. Recent advancements, such as the development of straight pore diffusion channels, have significantly ... electrolysis. However, the process requires thermal energy for water evaporation and temperature regulation. O-SOEC technology leads
[98] Revolutionizing Clean Hydrogen Production: The Breakthrough of Chemical — The research community is fervently exploring this technology, leading to the development of various chemical water-assisted electrolysis systems. The primary objective of the recent review published in Industrial Chemistry & Materials is to equip readers with a comprehensive understanding of the current research trends and innovative catalyst design strategies pertinent to chemical-assisted water electrolysis. With continued research and development, including insights from recent literature reviews and experimental studies, the horizon for chemical water-assisted electrolysis is bright, promising to deliver enhanced energy efficiency in hydrogen production. Subject of Research: Chemical-assisted water electrolysis for green hydrogen production Clean hydrogen, chemical water-assisted electrolysis, green energy, catalyst design, energy efficiency, low-voltage operation, hydrogen production, environmental sustainability, membrane electrode assembly, fuel cells, long-term stability, industrial applications.
[99] Advances in steam electrolysis for green hydrogen production: Current ... — Electrolytic hydrogen production methods include alkaline water electrolysis (AWE), proton exchange membrane (PEM) electrolysis, and anion exchange membrane (AEM) electrolysis. Alkaline Water Electrolysis (AWE) is a well-known commercial process that operates at 30-90 °C using nickel electrodes and achieving energy efficiencies of 62-82 %
[104] Breakthrough in solid-state hydrogen storage using reticular materials — Solid-state hydrogen storage using reticular materials, such as Metal-Organic Frameworks (MOFs), offers a promising alternative at low pressures and ambient temperatures without compromising storage capacity.
[105] MOFs-Based Materials for Solid-State Hydrogen Storage: Strategies and ... — Solid-state physical hydrogen storage relies primarily on the physisorption of hydrogen gas by porous materials. Within this context, MOFs have emerged as highly promising candidates due to their ultrahigh surface area, tunable pore dimensions, and rapid kinetics for hydrogen adsorption and desorption.
[107] A Review of High Density Solid Hydrogen Storage Materials by Pyrolysis ... — Hydrogen is one of the cleanest energies with potential to have zero carbon emission. Hydrogen storage is a challenging phase for the hydrogen energy application. The safety, cost, and transportation of compressed and liquified hydrogen hinder the widespread application of hydrogen energy. Chemical absorption of hydrogen in solid hydrogen storage materials is a promising hydrogen storage
[119] Integration of renewable energy sources in tandem with electrolysis: A ... — Integration of renewable energy sources in tandem with electrolysis: A technology review for green hydrogen production - ScienceDirect Integration of renewable energy sources in tandem with electrolysis: A technology review for green hydrogen production Despite its potential, integrating renewable energy with electrolysis to produce green hydrogen faces significant technological and economic challenges, particularly in achieving high efficiency and cost-effectiveness at scale. This review systematically examines the latest advancements in electrolysis technologies—alkaline, proton exchange membrane electrolysis cell (PEMEC), and solid oxide—and explores innovative grid integration and energy storage solutions that enhance the viability of green hydrogen. The integration of these technologies could revolutionise energy systems worldwide, aligning with policy frameworks and market dynamics to foster broader adoption of green hydrogen. For all open access content, the relevant licensing terms apply.
[122] Integration of Renewable-Energy-Based Green Hydrogen into the ... - MDPI — Environmental Impact: Green hydrogen production offers a sustainable alternative to conventional hydrogen production methods, which often rely on fossil fuels. By utilizing renewable energy sources, green hydrogen can significantly reduce greenhouse gas emissions, air pollution, and dependence on finite fossil fuel resources.
[138] Hydrogen-Helium Abundance - HyperPhysics — Hydrogen-Helium Abundance Hydrogen and helium account for nearly all the nuclear matter in today's universe. This is consistent with the standard or "big bang" model.The process of forming the hydrogen and helium and other trace constituents is often called "big bang nucleosynthesis".Schramm's figures for relative abundances indicate that helium is about 25% by mass and hydrogen about 73% with
[139] What Is the Most Abundant Element in the Universe? - Science Notes and ... — Hydrogen is the most abundant element in the universe, followed by helium. Oxygen accounts for about 1 percent. All the other elements together only account for a bit more than one percent! The most abundant element in the universe is hydrogen. Hydrogen accounts for nearly three-quarters of all matter, while helium makes up nearly one-quarter
[142] The Genesis of Hydrogen: The Most Abundant Element in the Universe — Stellar Nucleosynthesis: Hydrogen in Stars Stellar Formation: Hydrogen continued to play a pivotal role in the evolution of the universe as stars began to form. The immense gravitational pressure within stellar cores caused hydrogen atoms to fuse, giving birth to helium through a process known as nuclear fusion.
[145] Key ingredient of galaxy formation measured - Nature — Given that atomic hydrogen is a key ingredient in the recipe for star formation, the discovery of an excess of this gas in distant galaxies helps explain the high star-formation rate at those
[146] Experimental Results for H2 Formation from H− and H and ... - Science — Formation of molecular hydrogen through electron-expelling collisions of H atoms and H − anions is regarded as a key step in the cooling process that led to assembly of the first stars in the early universe.
[148] Early star-forming galaxies and the reionization of the Universe — Intense ultraviolet radiation from these early galaxies probably induced a major event in cosmic history: the reionization of intergalactic hydrogen. Star-forming galaxies trace cosmic history.
[149] Making the First Stars | Center for Astrophysics | Harvard & Smithsonian — These stars thus altered in a fundamental way the chemical and thermal state of the gas from which the first galaxies then formed, in turn triggering the first self-sustaining cycle of star formation, feedback, and chemical enrichment.
[186] Hydrogen ion - Wikipedia — A hydrogen ion is created when a hydrogen atom ... The hydrogen anion, with its loosely held two-electron cloud, has a larger radius than the neutral atom, which in turn is much larger than the bare proton of the cation. ... More reactants added to a system yield more product production (the chemical reaction shifts to the right) and if more
[190] Explain the following. Hydrogen shows similarity with alkali metals as ... — Therefore, some chemical properties of hydrogen are similar to those of alkali metals while some resemble halogens. Hence, hydrogen shows similarity with alkali metals as well as halogens.
[193] PDF — However, in terms of reactivity, it is very low as compared to halogens. Inspite of the fact that hydrogen, to a certain extent resembles both with alkali metals and halogens, it differs from them as well. Now the pertinent question arises as where should it be placed in the periodic table? Loss of the electron from hydrogen atom
[194] Explain the following. Hydrogen shows similarity with alkali metals as ... — Electronic configuration of hydrogen is 1s 1 which is similar to the outer electronic configuration of alkali metals of group 1 i.e., ns 1.; However, 1s 1 also resembles the outer electronic configuration of group 17 elements i.e., ns 2 np 5.; By adding one electron to H, it will attain the electronic configuration of the inert gas He which is 1s 2, and by adding one electron to ns 2 np 5 we
[195] Why does hydrogen appear to be separated from the rest of the table ... — While hydrogen shares some periodic trends with the alkali metals in Group 1 and halogens in Group 17, it differs significantly in properties like ionization energy, electronegativity, metallic nature, atomic size, and electron configuration. Hydrogen's chemistry does not align fully with any group. Summary
[196] 21.3: Hydrogen - Chemistry LibreTexts — Because of its 1s1 electron configuration and the fact that the 1s orbital can accommodate no more than two electrons, hydrogen can (a) bond to other elements by losing an electron to form a proton, which can accept a pair of electrons from a more electronegative atom to form a polar covalent bond; (b) gain an electron from an electropositive metal to form a hydride ion, resulting in an ionic hydride; or (c) share its half-filled 1s orbital with a half-filled orbital on another atom to form a covalent or a polar covalent electron-pair bond. Hydrogen can form compounds that contain a proton (H+), a hydride ion (H−), an electron-pair bond to H, a hydrogen bond, or a three-center bond (or electron-deficient bond), in which two electrons are shared between three atoms.
[209] Position of Hydrogen - Chemistry, Class 11, Hydrogen — 3) In some hydrogen differs from both alkali metals and halogens. 2) Electropositive character: Like alkali metals ,hydrogen also loses its only electron to form hydrogen ion i.e. H+ 4) Combination with electronegative elements or non metals: Like alkali metals, hydrogen combines with electronegative elements such as oxygen ,halogen and sulphur forming their oxides ,halides and sulphide. 1) Hydrogen is less electropositive than alkali metals and less electronegative than halogens. Hydrogen has less tendency to form H+ ions as compared to alkali metals which readily form monovalent cation. Filed Under: Chemistry, Class 11, Hydrogen Tagged With: Difference from Alkali metal and halogens, Resemblance with alkali metals, Resemblance with halogens, Unique position of Hydrogen in periodic table
[210] Position Of Hydrogen In Periodic Table - Elements Of Hydrogen - BYJU'S — What is the Position of Hydrogen in the Periodic Table? Hydrogen is the first element of the periodic table as its atomic number is one, which means it has only one electron in its atom and thus only one electron is present in its outermost shell. The placement of elements in the periodic table is based on their electronic configuration.
[211] 22.6: Hydrogen: A Unique Element - Chemistry LibreTexts — Most versions of the periodic table place hydrogen in the upper left corner immediately above lithium, implying that hydrogen, with a 1s 1 electron configuration, is a member of group 1. In fact, the chemistry of hydrogen does not greatly resemble that of the metals of Group 1.
[214] (PDF) Hydrogen - Some Historical Highlights - ResearchGate — The early history of experiments in which an inflammable air was prepared is outlined. Once hydrogen had been discovered by Cavendish in 1766, the world of science and technology was given a
[215] The periodic table | CPD | RSC Education — The position of hydrogen can often lead to confusion as different versions of the periodic table place it differently: at the top of group 1 or 7 or somewhere in between.
[229] 10 Uses of Hydrogen | For Industry and Everyday Life - Study Read — Important Uses of Hydrogen Hydrogen is the first element in the periodic table, with an atomic number of 1 and a weight of 1.008. Hydrogen gas is one of the gases used for the welding process. Besides generating heat, hydrogen also acts as a shielding gas. Hydrogen gas is widely used in the petroleum industry to remove sulfur content. Hydrogen gas in the form of deuterium (D2) is used in deuterium arc lamps. One of the first uses of Hydrogen gas was in flying hot balloons in the air. Hydrogen fuel If anyone can help to find out, can the electricity be converted to hydrogen gas? But hydrogen is used on daily basis in petroleum industry, in gas welding and also in research labs for chemical analysis. 1.008. Hydrogen gas is one of the gases used for the welding process. Besides generating heat, hydrogen also acts as a shielding gas. Hydrogen gas is widely used in the petroleum industry to remove sulfur content. Hydrogen gas in the form of deuterium (D2) is used in deuterium arc lamps. One of the first uses of Hydrogen gas was in flying hot balloons in the air. Hydrogen fuel If anyone can help to find out, can the electricity be converted to hydrogen gas? But hydrogen is used on daily basis in petroleum industry, in gas welding and also in research labs for chemical analysis.
[230] 10 Common Uses of Hydrogen — Also, hydrogen is a highly flammable element. These two aspects are the main reason why hydrogen is used as rocket fuel. 3. Food Industry. Most of the manufactured food acids and bases contain hydrogen as one of their components. Hydrogen is also used in the food industry due to its ability to break down fats. 4. Ammonia Fertilizer. Hydrogen is
[231] Uses of Hydrogen in Industry - Features - The Chemical Engineer — Uses of Hydrogen in Industry - Features - The Chemical Engineer The Haber-Bosch process is the main industrial procedure for the production of ammonia today, and involves the direct combination of hydrogen and nitrogen under pressure and temperature in the presence of a metal catalyst. Hydrogen peroxide is typically made in a multi-step, energy-intensive process that requires it to be produced in large quantities and shipped and stored in a highly concentrated form. More recently, researchers from the UK and the US have developed a method of producing H2O2 on demand through a simple, one-step process, allowing dilute H2O2 to be made directly from hydrogen and oxygen in small quantities on site. Chemicals Energy Environment Equipment Industry Industrial Gases Metals Oil & Gas Refining Research & Development Clean Energy SIG: The Hydrogen Economy Hydrogen
[232] Hydrogen in Industrial Application - FCHEA - Fuel Cell & Hydrogen ... — Thanks to the development of the hydrogen industry in the 20th century, utilizing hydrogen in industrial practices is fairly widespread. Hydrogen is essential to the modern ammonia industry, for example, where the Haber-Bosch process combines hydrogen and nitrogen to produce ammonia. Ammonia is commonly used as a critical component of fertilizers, and as a result more than half of the world
[233] Top Industrial Uses of Hydrogen | Industrial Hydrogen Safety — WHA International offers safety services for the growing hydrogen industry, for both industrial applications and emerging technologies. The lion’s share of hydrogen usage actually goes to industrial applications. Hydrogen Energy Industry Applications WHA: Helping Keep Industry Safe Around Hydrogen Our consultants have played pivotal roles in the technology development and safe use of hydrogen and are uniquely equipped to address industry concerns in hydrogen safety. To keep industry safe from the hazards of hydrogen, WHA offers hazard analysis, custom testing, and other specialized safety services. WHA International is ready to support industry’s hydrogen safety needs. No matter the industry or final application, hydrogen safety considerations will allow us to make true progress toward more efficient and cleaner means of production.
[242] Hydrogen integration in power grids, infrastructure demands and techno ... — Hydrogen's unique property makes it desirable to stabilize intermittent renewable energy sources and offer effective long-term energy storage options. Nevertheless, the effective incorporation of hydrogen into the present electricity system requires substantial alterations and enhancements to the existing infrastructure .
[247] Exploring cutting-edge advances in green ammonia production and storage ... — Ammonia synthesis by electro-catalytic processes can provide an alternative option to the thermal catalyst rotheyte, and it is a widely used technology with zero carbon emission and promoting reducing carbon footprint . It can help the chemical industry's need for ammonia with pollution-free water at lower temperatures and pressure.
[248] Improving Ammonia Production Sustainability — Ammonia production, a cornerstone of global food security, carries a significant environmental footprint. While its output is essential for producing fertilizers to feed billions, it accounts for 1.8% of global CO 2 emissions, releasing around 500 million tonnes annually. The energy demands are also significant, consuming 3% - 5% of global natural gas and 1.8% of total energy output.
[249] Rocket Fuel Innovations: How Efficient Are New Propulsion Systems ... — Unlike chemical rockets, which burn fuel for thrust, NTP systems use a nuclear reactor to heat liquid hydrogen, turning it into an ultra-hot gas that expands through a nozzle to create thrust. With an ISP of 800-1000 seconds, NTP engines are almost twice as efficient as traditional chemical propulsion.
[251] The Evolution of Spacecraft Fuel: Pioneering Suppliers in Sustainable ... — These propellants promise to reduce the environmental impact of rocket launches compared to traditional hypergolic fuels. How do biofuels compare to traditional rocket fuels in terms of performance and sustainability? Biofuels are gaining attention for their lower carbon footprint and potential to be synthesized from renewable resources.
[275] Impact of hydrogen on the environment - ScienceDirect — Hydrogen available on the market at present is mainly generated by using steam reforming of natural gas, which is a fossil fuel. It is essential to note, however, that hydrogen generation from fossil fuels, such as natural gas and coal, leads to the emission of greenhouse gases and, therefore, is not environmentally friendly. Consequently, in the development of hydrogen technologies we must realise that hydrogen generation is environmentally friendly only when obtained by using renewable energy. Hydrogen generated from fossil fuels, such as steam reforming of natural gas, is not environmentally clean. Hydrogen is environmentally friendly only when is generated by using renewable energy. Hydrogen generated from water by using solar energy (solar-hydrogen) is environmentally friendly and, therefore, is expected to be the fuel of the future.
[279] Environmental Benefits of Natural Hydrogen Compared to Fossil Fuels — Introduction. Natural hydrogen offers an exciting promise of sustainability for a world that urgently needs it. Unlike fossil fuels, which are notorious for CO₂ emissions and other pollutants, hydrogen is clean-burning, with only water vapor as a byproduct.This characteristic alone puts hydrogen at the forefront of eco-friendly energy sources, but the environmental advantages of natural
[280] Hydrogen energy advantages compared to fossil fuels — Abundant hydrogen supply enables energy independence. Another compelling advantage of hydrogen energy is its potential to enhance energy independence for countries around the world. Unlike fossil fuels, which are concentrated in specific geographical regions, hydrogen can be produced virtually anywhere, using a variety of methods and resources.
[283] Environmental impact assessment and comparison of some hydrogen ... — For the fossil fuels based hydrogen production, steam methane reforming (SMR) of natural gas is studied. The environmental impacts results of the hydrogen production processes indicate that SMR of natural gas has the highest environmental impacts in terms of abiotic depletion, global warming potential, and other impact categories. used exergetic life cycle assessment on hydrogen production from renewables such as solar and wind to evaluate exergy and economic efficiencies and environmental impacts. Acar and Dincer compared different hydrogen production methods in order to assess their economic, social and environmental impacts. This paper has comprehensively studied the environmental impacts of hydrogen production using different methods such as steam methane reforming, electrolysis with different cells and energy sources from fossil to renewable.
[284] Government Policies and Incentives for Hydrogen Development — The government is promoting policies to integrate renewable energy with hydrogen production, ensuring sustainability and economic viability. Strategic Partnerships India is forging strategic partnerships with countries such as Japan, Germany, and Australia to collaborate on hydrogen technology and infrastructure development.
[285] Green hydrogen production's impact on sustainable development goals — Green hydrogen production's impact on sustainable development goals - ScienceDirect As a result, the objective of this review is to provide a complete analysis of green hydrogen production's contributions to the SDGs. It also means review its impacts, identifying critical challenges, including cost competitiveness, infrastructure scalability, and sustainable resource management, particularly regarding water use. ODS 7: Affordable and Clean Energy - Green hydrogen production is dependent on electricity generated from clean and renewable energy sources, as solar or wind. Green hydrogen: a pathway to a sustainable energy future Hydrogen production, storage, transportation and utilization for energy sector: a current status review A green hydrogen economy for a renewable energy society Modeling and economic evaluation of hybrid renewable energy sources for green hydrogen production: A case study for the Mediterranean region
[299] Challenges and Limitations - World Hydrogen Energy Organization — Hydrogen Energy Menu Toggle Navigating the Complexities: Addressing Challenges and Limitations in Hydrogen Energy Hydrogen energy projects require significant upfront investment, ranging from research and development to infrastructure deployment and commercialization. To create an enabling environment for hydrogen energy, policymakers must develop comprehensive and coherent policy frameworks that support research, development, deployment, and commercialization of hydrogen technologies. Addressing the challenges and limitations of hydrogen energy requires concerted efforts and collaboration among stakeholders from government, industry, academia, and civil society. By advancing technological innovation, promoting economic development, enacting supportive policies, and engaging with diverse communities, we can overcome barriers and unlock the full potential of hydrogen as a clean, reliable, and sustainable energy source. Hydrogen Energy Menu Toggle
[305] From Waste to Green Hydrogen: Breaking Barriers — The global transition to sustainable energy faces a critical hurdle in the adoption of green hydrogen. Despite its potential as a clean and versatile energy carrier, green hydrogen remains limited in its adoption due to two significant challenges: high production costs and complex distribution logistics. ... The Cost Barrier: Why Green Hydrogen
[306] Challenges and Limitations - World Hydrogen Energy Organization — Hydrogen Energy Menu Toggle Navigating the Complexities: Addressing Challenges and Limitations in Hydrogen Energy Hydrogen energy projects require significant upfront investment, ranging from research and development to infrastructure deployment and commercialization. To create an enabling environment for hydrogen energy, policymakers must develop comprehensive and coherent policy frameworks that support research, development, deployment, and commercialization of hydrogen technologies. Addressing the challenges and limitations of hydrogen energy requires concerted efforts and collaboration among stakeholders from government, industry, academia, and civil society. By advancing technological innovation, promoting economic development, enacting supportive policies, and engaging with diverse communities, we can overcome barriers and unlock the full potential of hydrogen as a clean, reliable, and sustainable energy source. Hydrogen Energy Menu Toggle
[307] Hydrogen as an alternative fuel: A comprehensive review of challenges ... — Hydrogen as an alternative fuel: A comprehensive review of challenges and opportunities in production, storage, and transportation - ScienceDirect Hydrogen as an alternative fuel: A comprehensive review of challenges and opportunities in production, storage, and transportation Evaluated opportunities in hydrogen production, storage, and transport systems. At present, approximately 96% of global hydrogen production relies on fossil fuels, contributing to substantial emissions, while only 4% comes from water electrolysis. This review evaluates hydrogen's potential as a sustainable energy carrier, providing insights into advancements and ongoing challenges in production, storage, and transportation. Key findings highlight the necessity of coordinated efforts to enhance storage technologies, lower production costs, and establish supportive policies, highlighting hydrogen's critical role in achieving a sustainable energy transition. For all open access content, the Creative Commons licensing terms apply.
[308] Green Hydrogen Projects Face Implementation Challenges in 2025 — The study emphasises the necessity for hydrogen-specific support policies. Regulatory uncertainty and slow implementation of supportive measures in the European Union and the United States impede growth. A coherent policy strategy is essential to facilitate investment and guide the market towards viable hydrogen applications.