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81-400: Hydrogen ozonide ( H O 3 ) is a radical molecule consisting of a hydrogen atom covalently bonded to an ozonide unit. It is possibly produced in the reaction of the hydroxyl radical with dioxygen : OH + O 2 → HO 3 . It has been detected in a mass spectrometer experiment using HO 3 ( protonated ozone ) as precursor. This inorganic compound –related article

162-478: A coolant in the rotor and the stator in 1937 at Dayton , Ohio, owned by the Dayton Power & Light Co. This was justified by the high thermal conductivity and very low viscosity of hydrogen gas, thus lower drag than air. This is the most common coolant used for generators 60 MW and larger; smaller generators are usually air-cooled . The nickel–hydrogen battery was used for the first time in 1977 aboard

243-465: A nucleus which is usually composed of one proton. That is why H is often called a proton. This species is central to discussion of acids . Under the Brønsted–Lowry acid–base theory , acids are proton donors, while bases are proton acceptors. A bare proton, H , cannot exist in solution or in ionic crystals because of its strong attraction to other atoms or molecules with electrons. Except at

324-425: A renewable energy ). Hydrogen produced by electrolysis of water using renewable energy sources such as wind and solar power , referred to as green hydrogen . When derived from natural gas by zero greenhouse emission methane pyrolysis, it is referred to as turquoise hydrogen. When fossil fuel derived with greenhouse gas emissions , is generally referred to as grey hydrogen . If most of the carbon dioxide emission

405-494: A stoichiometric quantity of hydrogen at the anode. For hydrides other than group 1 and 2 metals, the term is quite misleading, considering the low electronegativity of hydrogen. An exception in group 2 hydrides is BeH 2 , which is polymeric. In lithium aluminium hydride , the [AlH 4 ] anion carries hydridic centers firmly attached to the Al(III). Although hydrides can be formed with almost all main-group elements,

486-437: A fire. Anaerobic oxidation of iron by the protons of water at high temperature can be schematically represented by the set of following reactions: Many metals such as zirconium undergo a similar reaction with water leading to the production of hydrogen. François Isaac de Rivaz built the first de Rivaz engine , an internal combustion engine powered by a mixture of hydrogen and oxygen in 1806. Edward Daniel Clarke invented

567-629: A molar basis ) because of its light weight, which enables it to escape the atmosphere more rapidly than heavier gases. However, hydrogen is the third most abundant element on the Earth's surface, mostly in the form of chemical compounds such as hydrocarbons and water. Hydrogen production Green hydrogen is usually understood to be produced from renewable electricity via electrolysis of water. Less frequently, definitions of green hydrogen include hydrogen produced from other low-emission sources such as biomass . Producing green hydrogen

648-448: A monatomic gas at cryogenic temperatures. According to quantum theory, this behavior arises from the spacing of the (quantized) rotational energy levels, which are particularly wide-spaced in H 2 because of its low mass. These widely spaced levels inhibit equal partition of heat energy into rotational motion in hydrogen at low temperatures. Diatomic gases composed of heavier atoms do not have such widely spaced levels and do not exhibit

729-545: A partial negative charge. These compounds are often known as hydrides . Hydrogen forms many compounds with carbon called the hydrocarbons , and even more with heteroatoms that, due to their association with living things, are called organic compounds . The study of their properties is known as organic chemistry and their study in the context of living organisms is called biochemistry . By some definitions, "organic" compounds are only required to contain carbon. However, most of them also contain hydrogen, and because it

810-477: A partial positive charge. When bonded to a more electronegative element, particularly fluorine , oxygen , or nitrogen , hydrogen can participate in a form of medium-strength noncovalent bonding with another electronegative element with a lone pair, a phenomenon called hydrogen bonding that is critical to the stability of many biological molecules. Hydrogen also forms compounds with less electronegative elements, such as metals and metalloids , where it takes on

891-405: A proton and an electron, the hydrogen atom , together with the spectrum of light produced from it or absorbed by it, has been central to the development of the theory of atomic structure. Furthermore, study of the corresponding simplicity of the hydrogen molecule and the corresponding cation H + 2 brought understanding of the nature of the chemical bond , which followed shortly after

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972-420: A range of other emerging electrochemical processes such as high temperature electrolysis or carbon assisted electrolysis. However, current best processes for water electrolysis have an effective electrical efficiency of 70-80%, so that producing 1 kg of hydrogen (which has a specific energy of 143 MJ/kg or about 40 kWh/kg) requires 50–55 kWh of electricity. In parts of the world, steam methane reforming

1053-467: A rotating electrolyser, where centrifugal force helps separate gas bubbles from water. Such an electrolyser at 15 bar pressure may consume 50 kilowatt-hours per kilogram (180 MJ/kg), and a further 15 kilowatt-hours (54 MJ) if the hydrogen is compressed for use in hydrogen cars. Conventional alkaline electrolysis has an efficiency of about 70%, however advanced alkaline water electrolysers with efficiency of up to 82% are available. Accounting for

1134-432: A second stage, additional hydrogen is generated through the lower-temperature, exothermic , water-gas shift reaction, performed at about 360 °C (680 °F): Essentially, the oxygen (O) atom is stripped from the additional water (steam) to oxidize CO to CO 2 . This oxidation also provides energy to maintain the reaction. Additional heat required to drive the process is generally supplied by burning some portion of

1215-538: A serious incident. Hydrogen-lifted airships were used as observation platforms and bombers during the war. The first non-stop transatlantic crossing was made by the British airship R34 in 1919. Regular passenger service resumed in the 1920s and the discovery of helium reserves in the United States promised increased safety, but the U.S. government refused to sell the gas for this purpose. Therefore, H 2

1296-440: A similar experiment with iron and sulfuric acid. However, in all likelihood, "sulfureous" should here be understood to mean "combustible". In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by naming the gas from a metal-acid reaction "inflammable air". He speculated that "inflammable air" was in fact identical to the hypothetical substance " phlogiston " and further finding in 1781 that

1377-401: A sizable amount of Hydrogen as a byproduct. In the port of Antwerp a 1MW demonstration fuel cell power plant is powered by such byproduct. This unit has been operational since late 2011. The excess hydrogen is often managed with a hydrogen pinch analysis. Gas generated from coke ovens in steel production is similar to Syngas with 60% hydrogen by volume. The hydrogen can be extracted from

1458-498: A smaller portion comes from energy-intensive methods such as the electrolysis of water . Its main industrial uses include fossil fuel processing, such as hydrocracking , and ammonia production , with emerging uses in fuel cells for electricity generation and as a heat source. When used in fuel cells, hydrogen's only emission at point of use is water vapor, though combustion can produce nitrogen oxides . Hydrogen's interaction with metals may cause embrittlement . Hydrogen gas

1539-471: A spark or flame, they do not react at room temperature in the absence of a catalyst. The ground state energy level of the electron in a hydrogen atom is −13.6  eV , equivalent to an ultraviolet photon of roughly 91 nm wavelength. The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, in which the electron "orbits" the proton, like how Earth orbits

1620-450: A species. To avoid the implication of the naked "solvated proton" in solution, acidic aqueous solutions are sometimes considered to contain a less unlikely fictitious species, termed the " hydronium ion" ( [H 3 O] ). However, even in this case, such solvated hydrogen cations are more realistically conceived as being organized into clusters that form species closer to [H 9 O 4 ] . Other oxonium ions are found when water

1701-406: A spin singlet state having spin S = 0 {\displaystyle S=0} . The equilibrium ratio of ortho- to para-hydrogen depends on temperature. At room temperature or warmer, equilibrium hydrogen gas contains about 25% of the para form and 75% of the ortho form. The ortho form is an excited state , having higher energy than the para form by 1.455 kJ/mol, and it converts to

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1782-438: A term that is used fairly loosely. The term "hydride" suggests that the H atom has acquired a negative or anionic character, denoted H ; and is used when hydrogen forms a compound with a more electropositive element. The existence of the hydride anion , suggested by Gilbert N. Lewis in 1916 for group 1 and 2 salt-like hydrides, was demonstrated by Moers in 1920 by the electrolysis of molten lithium hydride (LiH), producing

1863-482: A while before caus'd to be purposely fil'd off from a piece of good steel. This metalline powder being moistn'd in the viol with a little of the menstruum, was afterwards drench'd with more; whereupon the mixture grew very hot, and belch'd up copious and stinking fumes; which whether they consisted altogether of the volatile sulfur of the Mars [iron], or of metalline steams participating of a sulfureous nature, and join'd with

1944-579: Is exothermic and produces enough heat to evaporate most of the liquid if not converted first to parahydrogen during the cooling process. Catalysts for the ortho-para interconversion, such as ferric oxide and activated carbon compounds, are used during hydrogen cooling to avoid this loss of liquid. While H 2 is not very reactive under standard conditions, it does form compounds with most elements. Hydrogen can form compounds with elements that are more electronegative , such as halogens (F, Cl, Br, I), or oxygen ; in these compounds hydrogen takes on

2025-514: Is a stub . You can help Misplaced Pages by expanding it . Hydrogen Hydrogen is a chemical element ; it has symbol H and atomic number 1. It is the lightest element and, at standard conditions , is a gas of diatomic molecules with the formula H 2 , sometimes called dihydrogen , but more commonly called hydrogen gas , molecular hydrogen or simply hydrogen. It is colorless, odorless, non-toxic, and highly combustible . Constituting about 75% of all normal matter , hydrogen

2106-587: Is between $ 1–3/kg on average excluding hydrogen gas pressurization cost. This makes production of hydrogen via electrolysis cost competitive in many regions already, as outlined by Nel Hydrogen and others, including an article by the IEA examining the conditions which could lead to a competitive advantage for electrolysis. A small part (2% in 2019 ) is produced by electrolysis using electricity and water, consuming approximately 50 to 55 kilowatt-hours of electricity per kilogram of hydrogen produced. Water electrolysis

2187-910: Is captured, it is referred to as blue hydrogen. Hydrogen produced from coal may be referred to as brown or black hydrogen. Hydrogen is often referred to by various colors to indicate its origin (perhaps because gray symbolizes "dirty hydrogen" ). May also include electricity from low-emission sources such as biomass . 2 H 2 O → 2 H 2 + O 2 CH 4 → C + 2 H 2 1st stage: CH 4 + H 2 O → CO + 3 H 2 2nd stage: CO + H 2 O → CO 2 + H 2 1st stage: CH 4 + H 2 O → CO + 3 H 2 2nd stage: CO + H 2 O → CO 2 + H 2 1st stage: 3 C (i.e., coal) + O 2 + H 2 O → H 2 + 3 CO 2nd stage: CO + H 2 O → CO 2 + H 2 C 24 H 12 + 12 O 2 → 24 CO + 6 H 2 as black hydrogen H 2 O( l ) ⇌ H 2 ( g ) + 1/2 O 2 ( g )   2 H 2 O → 2 H 2 + O 2 2 H 2 O → 2 H 2 + O 2 2 H 2 O → 2 H 2 + O 2 Hydrogen

2268-505: Is crucial in acid-base reactions , which mainly involve proton exchange among soluble molecules. In ionic compounds , hydrogen can take the form of either a negatively charged anion , where it is known as hydride , or as a positively charged cation , H . The cation, usually just a proton (symbol p ), exhibits specific behavior in aqueous solutions and in ionic compounds involves screening of its electric charge by surrounding polar molecules or anions. Hydrogen's unique position as

2349-450: Is currently more expensive than producing gray hydrogen, and the efficiency of energy conversion is inherently low. Other methods of hydrogen production include biomass gasification , methane pyrolysis , and extraction of underground hydrogen . As of 2023, less than 1% of dedicated hydrogen production is low-carbon, i.e. blue hydrogen, green hydrogen, and hydrogen produced from biomass. In 2020, roughly 87 million tons of hydrogen

2430-416: Is detected in order to probe primordial hydrogen. The large amount of neutral hydrogen found in the damped Lyman-alpha systems is thought to dominate the cosmological baryonic density of the universe up to a redshift of z  = 4. Under ordinary conditions on Earth, elemental hydrogen exists as the diatomic gas, H 2 . Hydrogen gas is very rare in Earth's atmosphere (around 0.53 ppm on

2511-399: Is higher than steam reforming with carbon capture and higher than methane pyrolysis. One of the advantages of electrolysis over hydrogen from steam methane reforming (SMR) is that the hydrogen can be produced on-site, meaning that the costly process of delivery via truck or pipeline is avoided. In addition to reduce the voltage required for electrolysis via the increasing of the temperature of

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2592-400: Is highly flammable: Enthalpy of combustion : −286 kJ/mol. Hydrogen gas forms explosive mixtures with air in concentrations from 4–74% and with chlorine at 5–95%. The hydrogen autoignition temperature , the temperature of spontaneous ignition in air, is 500 °C (932 °F). Pure hydrogen-oxygen flames emit ultraviolet light and with high oxygen mix are nearly invisible to

2673-453: Is in acidic solution with other solvents. Although exotic on Earth, one of the most common ions in the universe is the H + 3 ion, known as protonated molecular hydrogen or the trihydrogen cation. Hydrogen has three naturally occurring isotopes, denoted H , H and H . Other, highly unstable nuclei ( H to H ) have been synthesized in the laboratory but not observed in nature. Unique among

2754-407: Is industrially produced from steam reforming (SMR), which uses natural gas. The energy content of the produced hydrogen is around 74% of the energy content of the original fuel, as some energy is lost as excess heat during production. In general, steam reforming emits carbon dioxide, a greenhouse gas, and is known as gray hydrogen. If the carbon dioxide is captured and stored, the hydrogen produced

2835-473: Is known as blue hydrogen. Steam methane reforming (SMR) produces hydrogen from natural gas, mostly methane (CH 4 ), and water. It is the cheapest source of industrial hydrogen, being the source of nearly 50% of the world's hydrogen. The process consists of heating the gas to 700–1,100 °C (1,300–2,000 °F) in the presence of steam over a nickel catalyst . The resulting endothermic reaction forms carbon monoxide and molecular hydrogen (H 2 ). In

2916-402: Is measured by energy consumed per standard volume of hydrogen (MJ/m ), assuming standard temperature and pressure of the H 2 . The lower the energy used by a generator, the higher would be its efficiency; a 100%-efficient electrolyser would consume 39.4 kilowatt-hours per kilogram (142 MJ/kg) of hydrogen, 12,749 joules per litre (12.75 MJ/m ). Practical electrolysis typically uses

2997-484: Is soluble in both nanocrystalline and amorphous metals . Hydrogen solubility in metals is influenced by local distortions or impurities in the crystal lattice . These properties may be useful when hydrogen is purified by passage through hot palladium disks, but the gas's high solubility is a metallurgical problem, contributing to the embrittlement of many metals, complicating the design of pipelines and storage tanks. Hydrogen compounds are often called hydrides ,

3078-537: Is still used, in preference to non-flammable but more expensive helium, as a lifting gas for weather balloons . Deuterium was discovered in December 1931 by Harold Urey , and tritium was prepared in 1934 by Ernest Rutherford , Mark Oliphant , and Paul Harteck . Heavy water , which consists of deuterium in the place of regular hydrogen, was discovered by Urey's group in 1932. The first hydrogen-cooled turbogenerator went into service using gaseous hydrogen as

3159-490: Is the most abundant chemical element in the universe . Stars , including the Sun , mainly consist of hydrogen in a plasma state , while on Earth, hydrogen is found in water , organic compounds , as dihydrogen , and in other molecular forms . The most common isotope of hydrogen (protium, H) consists of one proton , one electron , and no neutrons . In the early universe , the formation of hydrogen's protons occurred in

3240-412: Is the carbon-hydrogen bond that gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry. Millions of hydrocarbons are known, and they are usually formed by complicated pathways that seldom involve elemental hydrogen. Hydrogen is highly soluble in many rare earth and transition metals and

3321-655: Is using electricity to split water into hydrogen and oxygen. As of 2020, less than 0.1% of hydrogen production comes from water electrolysis. Electrolysis of water is 70–80% efficient (a 20–30% conversion loss) while steam reforming of natural gas has a thermal efficiency between 70 and 85%. The electrical efficiency of electrolysis is expected to reach 82–86% before 2030, while also maintaining durability as progress in this area continues apace. Water electrolysis can operate at 50–80 °C (120–180 °F), while steam methane reforming requires temperatures at 700–1,100 °C (1,300–2,000 °F). The difference between

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3402-502: The Hindenburg airship was a notorious example of hydrogen combustion and the cause is still debated. The visible flames in the photographs were the result of carbon compounds in the airship skin burning. H 2 is unreactive compared to diatomic elements such as halogens or oxygen. The thermodynamic basis of this low reactivity is the very strong H–H bond, with a bond dissociation energy of 435.7 kJ/mol. The kinetic basis of

3483-579: The International Union of Pure and Applied Chemistry (IUPAC) allows any of D, T, H , and H to be used, though H and H are preferred. The exotic atom muonium (symbol Mu), composed of an anti muon and an electron , can also be considered a light radioisotope of hydrogen. Because muons decay with lifetime 2.2  µs , muonium is too unstable for observable chemistry. Nevertheless, muonium compounds are important test cases for quantum simulation , due to

3564-492: The Kola Superdeep Borehole . It is unclear how much molecular hydrogen is available in natural reservoirs, but at least one company specializes in drilling wells to extract hydrogen. Most hydrogen in the lithosphere is bonded to oxygen in water. Manufacturing elemental hydrogen requires the consumption of a hydrogen carrier such as a fossil fuel or water. The former carrier consumes the fossil resource and in

3645-545: The water-gas shift reaction , the carbon monoxide reacts with steam to obtain further quantities of H 2 . The WGSR also requires a catalyst, typically over iron oxide or other oxides . The byproduct is CO 2 . Depending on the quality of the feedstock (natural gas, naphtha , etc.), one ton of hydrogen produced will also produce 9 to 12 tons of CO 2 , a greenhouse gas that may be captured . For this process, high temperature steam (H 2 O) reacts with methane (CH 4 ) in an endothermic reaction to yield syngas . In

3726-431: The "planetary orbit" differs from electron motion. Molecular H 2 exists as two spin isomers , i.e. compounds that differ only in the spin states of their nuclei. In the orthohydrogen form, the spins of the two nuclei are parallel, forming a spin triplet state having a total molecular spin S = 1 {\displaystyle S=1} ; in the parahydrogen form the spins are antiparallel and form

3807-618: The Department of Energy hydrogen production targets for 2015, the hydrogen cost is $ 3/kg. The US DOE target price for hydrogen in 2020 is $ 2.30/kg, requiring an electricity cost of $ 0.037/kWh, which is achievable given recent PPA tenders for wind and solar in many regions. The report by IRENA.ORG is an extensive factual report of present-day industrial hydrogen production consuming about 53 to 70 kWh per kg could go down to about 45 kWh/kg H 2 . The thermodynamic energy required for hydrogen by electrolysis translates to 33 kWh/kg, which

3888-479: The Sun and other stars). The charged particles are highly influenced by magnetic and electric fields. For example, in the solar wind they interact with the Earth's magnetosphere giving rise to Birkeland currents and the aurora . Hydrogen is found in the neutral atomic state in the interstellar medium because the atoms seldom collide and combine. They are the source of the 21-cm hydrogen line at 1420 MHz that

3969-457: The Sun and the CNO cycle of nuclear fusion in case of stars more massive than the Sun . Throughout the universe, hydrogen is mostly found in the atomic and plasma states, with properties quite distinct from those of molecular hydrogen. As a plasma, hydrogen's electron and proton are not bound together, resulting in very high electrical conductivity and high emissivity (producing the light from

4050-464: The Sun. However, the electron and proton are held together by electrostatic attraction, while planets and celestial objects are held by gravity . Due to the discretization of angular momentum postulated in early quantum mechanics by Bohr, the electron in the Bohr model can only occupy certain allowed distances from the proton, and therefore only certain allowed energies. A more accurate description of

4131-663: The U.S. Navy's Navigation technology satellite-2 (NTS-2). The International Space Station , Mars Odyssey and the Mars Global Surveyor are equipped with nickel-hydrogen batteries. In the dark part of its orbit, the Hubble Space Telescope is also powered by nickel-hydrogen batteries, which were finally replaced in May 2009, more than 19 years after launch and 13 years beyond their design life. Because of its simple atomic structure, consisting only of

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4212-406: The coke oven gas economically. Hydrogen production from natural gas and heavier hydrocarbons is achieved by partial oxidation. A fuel-air or fuel-oxygen mixture is partially combusted , resulting in a hydrogen- and carbon monoxide-rich syngas. More hydrogen and carbon dioxide are then obtained from carbon monoxide (and water) via the water-gas shift reaction. Carbon dioxide can be co-fed to lower

4293-436: The cost of hydrogen by electrolysis is around $ 3–8/kg. Considering the industrial production of hydrogen, and using current best processes for water electrolysis (PEM or alkaline electrolysis) which have an effective electrical efficiency of 70–82%, producing 1 kg of hydrogen (which has a specific energy of 143 MJ/kg or about 40 kWh/kg) requires 50–55 kWh of electricity. At an electricity cost of $ 0.06/kWh, as set out in

4374-480: The electrolysis cell it is also possible to electrochemically consume the oxygen produced in an electrolyser by introducing a fuel (such as carbon/coal, methanol , ethanol , formic acid , glycerol, etc.) into the oxygen side of the reactor. This reduces the required electrical energy and has the potential to reduce the cost of hydrogen to less than 40~60% with the remaining energy provided in this manner. Carbon/hydrocarbon assisted water electrolysis (CAWE) has

4455-430: The elements, distinct names are assigned to its isotopes in common use. During the early study of radioactivity, heavy radioisotopes were given their own names, but these are mostly no longer used. The symbols D and T (instead of H and H ) are sometimes used for deuterium and tritium, but the symbol P was already used for phosphorus and thus was not available for protium. In its nomenclatural guidelines,

4536-497: The first reliable form of air-travel following the 1852 invention of the first hydrogen-lifted airship by Henri Giffard . German count Ferdinand von Zeppelin promoted the idea of rigid airships lifted by hydrogen that later were called Zeppelins ; the first of which had its maiden flight in 1900. Regularly scheduled flights started in 1910 and by the outbreak of World War I in August 1914, they had carried 35,000 passengers without

4617-496: The first second after the Big Bang ; neutral hydrogen atoms only formed about 370,000 years later during the recombination epoch as the universe cooled and plasma had cooled enough for electrons to remain bound to protons. Hydrogen, typically nonmetallic except under extreme pressure , readily forms covalent bonds with most nonmetals, contributing to the formation of compounds like water and various organic substances. Its role

4698-462: The gas produces water when burned. He is usually given credit for the discovery of hydrogen as an element. In 1783, Antoine Lavoisier identified the element that came to be known as hydrogen when he and Laplace reproduced Cavendish's finding that water is produced when hydrogen is burned. Lavoisier produced hydrogen for his experiments on mass conservation by reacting a flux of steam with metallic iron through an incandescent iron tube heated in

4779-427: The high temperatures associated with plasmas, such protons cannot be removed from the electron clouds of atoms and molecules, and will remain attached to them. However, the term 'proton' is sometimes used loosely and metaphorically to refer to positively charged or cationic hydrogen attached to other species in this fashion, and as such is denoted " H " without any implication that any single protons exist freely as

4860-503: The hydrogen atom comes from a quantum analysis that uses the Schrödinger equation , Dirac equation or Feynman path integral formulation to calculate the probability density of the electron around the proton. The most complex formulas include the small effects of special relativity and vacuum polarization . In the quantum mechanical treatment, the electron in a ground state hydrogen atom has no angular momentum—illustrating how

4941-399: The hydrogen gas blowpipe in 1819. The Döbereiner's lamp and limelight were invented in 1823. Hydrogen was liquefied for the first time by James Dewar in 1898 by using regenerative cooling and his invention, the vacuum flask . He produced solid hydrogen the next year. The first hydrogen-filled balloon was invented by Jacques Charles in 1783. Hydrogen provided the lift for

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5022-469: The hydrogen production is large enough. SOECs operate at high temperatures, typically around 800 °C (1,500 °F). At these high temperatures, a significant amount of the energy required can be provided as thermal energy (heat), and as such is termed high-temperature electrolysis . The heat energy can be provided from a number of different sources, including waste industrial heat, nuclear power stations or concentrated solar thermal plants . This has

5103-400: The low reactivity is the nonpolar nature of H 2 and its weak polarizability. It spontaneously reacts with chlorine and fluorine to form hydrogen chloride and hydrogen fluoride , respectively. The reactivity of H 2 is strongly affected by the presence of metal catalysts. Thus, while mixtures of H 2 with O 2 or air combust readily when heated to at least 500°C by

5184-402: The mass difference between the antimuon and the proton, and IUPAC nomenclature incorporates such hypothetical compounds as muonium chloride (MuCl) and sodium muonide (NaMu), analogous to hydrogen chloride and sodium hydride respectively. Table of thermal and physical properties of hydrogen (H 2 ) at atmospheric pressure: In 1671, Irish scientist Robert Boyle discovered and described

5265-481: The mass of the universe, however, is not in the form of chemical-element type matter, but rather is postulated to occur as yet-undetected forms of mass such as dark matter and dark energy . Hydrogen is found in great abundance in stars and gas giant planets. Molecular clouds of H 2 are associated with star formation . Hydrogen plays a vital role in powering stars through the proton-proton reaction in case of stars with very low to approximately 1 mass of

5346-588: The methane. Methods to produce hydrogen without the use of fossil fuels involve the process of water splitting , or splitting the water molecule (H 2 O) into its components oxygen and hydrogen. When the source of energy for water splitting is renewable or low-carbon, the hydrogen produced is sometimes referred to as green hydrogen . The conversion can be accomplished in several ways, but all methods are currently considered more expensive than fossil-fuel based production methods. Hydrogen can be made via high pressure electrolysis , low pressure electrolysis of water, or

5427-501: The naked eye, as illustrated by the faint plume of the Space Shuttle Main Engine , compared to the highly visible plume of a Space Shuttle Solid Rocket Booster , which uses an ammonium perchlorate composite . The detection of a burning hydrogen leak, may require a flame detector ; such leaks can be very dangerous. Hydrogen flames in other conditions are blue, resembling blue natural gas flames. The destruction of

5508-649: The number and combination of possible compounds varies widely; for example, more than 100 binary borane hydrides are known, but only one binary aluminium hydride. Binary indium hydride has not yet been identified, although larger complexes exist. In inorganic chemistry , hydrides can also serve as bridging ligands that link two metal centers in a coordination complex . This function is particularly common in group 13 elements , especially in boranes ( boron hydrides) and aluminium complexes, as well as in clustered carboranes . Oxidation of hydrogen removes its electron and gives H , which contains no electrons and

5589-655: The only neutral atom for which the Schrödinger equation can be directly solved, has significantly contributed to the foundational principles of quantum mechanics through the exploration of its energetics and chemical bonding . Hydrogen gas was first produced artificially in the early 16th century by reacting acids with metals. Henry Cavendish , in 1766–81, identified hydrogen gas as a distinct substance and discovered its property of producing water when burned; hence its name means "water-former" in Greek. Most hydrogen production occurs through steam reforming of natural gas ;

5670-420: The para form over the course of several minutes when cooled to low temperature. The thermal properties of the forms differ because they differ in their allowed rotational quantum states , resulting in different thermal properties such as the heat capacity. The ortho-to-para ratio in H 2 is an important consideration in the liquefaction and storage of liquid hydrogen : the conversion from ortho to para

5751-516: The potential to offer a less energy intensive, cleaner method of using chemical energy in various sources of carbon, such as low-rank and high sulfur coals, biomass, alcohols and methane (Natural Gas), where pure CO 2 produced can be easily sequestered without the need for separation. Biomass is converted into syngas by gasification and syngas is further converted into hydrogen by water-gas shift reaction (WGSR). The industrial production of chlorine and caustic soda by electrolysis generates

5832-642: The potential to reduce the overall cost of the hydrogen produced by reducing the amount of electrical energy required for electrolysis. PEM electrolysis cells typically operate below 100 °C (212 °F). These cells have the advantage of being comparatively simple and can be designed to accept widely varying voltage inputs, which makes them ideal for use with renewable sources of energy such as photovoltaic solar panels . AECs optimally operate at high concentrations of electrolyte (KOH or potassium carbonate ) and at high temperatures, often near 200 °C (392 °F). Efficiency of modern hydrogen generators

5913-477: The quantum mechanical treatment of the hydrogen atom had been developed in the mid-1920s. One of the first quantum effects to be explicitly noticed (but not understood at the time) was a Maxwell observation involving hydrogen, half a century before full quantum mechanical theory arrived. Maxwell observed that the specific heat capacity of H 2 unaccountably departs from that of a diatomic gas below room temperature and begins to increasingly resemble that of

5994-502: The reaction between iron filings and dilute acids , which results in the production of hydrogen gas. Having provided a saline spirit [hydrochloric acid], which by an uncommon way of preparation was made exceeding sharp and piercing, we put into a vial, capable of containing three or four ounces of water, a convenient quantity of filings of steel, which were not such as are commonly sold in shops to Chymists and Apothecaries, (those being usually not free enough from rust) but such as I had

6075-506: The saline exhalations of the menstruum, is not necessary to be here discuss'd. But whencesoever this stinking smoak proceeded, so inflammable it was, that upon the approach of a lighted candle to it, it would readily enough take fire, and burn with a blewish and somewhat greenish flame at the mouth of the viol for a good while together; and that, though with little light, yet with more strength than one would easily suspect. The word "sulfureous" may be somewhat confusing, especially since Boyle did

6156-405: The same effect. Antihydrogen ( H ) is the antimatter counterpart to hydrogen. It consists of an antiproton with a positron . Antihydrogen is the only type of antimatter atom to have been produced as of 2015 . Hydrogen, as atomic H, is the most abundant chemical element in the universe, making up 75% of normal matter by mass and >90% by number of atoms. Most of

6237-412: The steam methane reforming (SMR) process produces greenhouse gas carbon dioxide. However, in the newer methane pyrolysis process no greenhouse gas carbon dioxide is produced. These processes typically require no further energy input beyond the fossil fuel. Decomposing water, the latter carrier, requires electrical or heat input, generated from some primary energy source (fossil fuel, nuclear power or

6318-965: The two methods is the primary energy used; either electricity (for electrolysis) or natural gas (for steam methane reforming). Due to their use of water, a readily available resource, electrolysis and similar water-splitting methods have attracted the interest of the scientific community. With the objective of reducing the cost of hydrogen production, renewable sources of energy have been targeted to allow electrolysis. There are three main types of electrolytic cells , solid oxide electrolyser cells (SOECs), polymer electrolyte membrane cells (PEM) and alkaline electrolysis cells (AECs). Traditionally, alkaline electrolysers are cheaper in terms of investment (they generally use nickel catalysts), but less-efficient; PEM electrolysers, conversely, are more expensive (they generally use expensive platinum group metal catalysts) but are more efficient and can operate at higher current densities , and can therefore be possibly cheaper if

6399-431: The use of the higher heat value (because inefficiency via heat can be redirected back into the system to create the steam required by the catalyst), average working efficiencies for PEM electrolysis are around 80%, or 82% using the most modern alkaline electrolysers. PEM efficiency is expected to increase to approximately 86% before 2030. Theoretical efficiency for PEM electrolysers is predicted up to 94%. As of 2020,

6480-456: Was produced worldwide for various uses, such as oil refining , in the production of ammonia through the Haber process , and in the production of methanol through reduction of carbon monoxide . The global hydrogen generation market was fairly valued at US$ 155 billion in 2022, and expected to grow at a compound annual growth rate of 9.3% from 2023 to 2030. Molecular hydrogen was discovered in

6561-527: Was used in the Hindenburg airship, which was destroyed in a midair fire over New Jersey on 6 May 1937. The incident was broadcast live on radio and filmed. Ignition of leaking hydrogen is widely assumed to be the cause, but later investigations pointed to the ignition of the aluminized fabric coating by static electricity . But the damage to hydrogen's reputation as a lifting gas was already done and commercial hydrogen airship travel ceased . Hydrogen

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