Hydrogen technologies are

technologies Technology is the application of knowledge to reach practical goals in a specifiable and reproducible way. The word ''technology'' may also mean the product of such an endeavor. The use of technology is widely prevalent in medicine, science, ...

that relate to the

production Production may refer to: Economics and business * Production (economics) * Production, the act of manufacturing goods * Production, in the outline of industrial organization, the act of making products (goods and services) * Production as a stati ...

and use of

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

as a part

hydrogen economy The hydrogen economy is using hydrogen to decarbonize economic sectors which are hard to electrify, essentially, the "hard-to-abate" sectors such as cement, steel, long-haul transport etc. In order to phase out fossil fuels and limit climate ch ...

. Hydrogen technologies are applicable for many uses. Some hydrogen technologies are

carbon neutral Carbon neutrality is a state of net-zero carbon dioxide emissions. This can be achieved by balancing emissions of carbon dioxide with its removal (often through carbon offsetting) or by eliminating emissions from society (the transition to the "p ...

and could have a role in preventing

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...

and a possible future

. Hydrogen is a chemical widely used in various applications including

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

production, oil refining and energy. The most common methods for producing hydrogen on an industrial scale are:

Steam reforming Steam reforming or steam methane reforming (SMR) is a method for producing syngas (hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly natural gas is the feedstock. The main purpose of this technology is hydrogen product ...

, oil reforming, coal gasification,

water electrolysis Electrolysis of water, also known as electrochemical water splitting, is the process of using electricity to decompose water into oxygen and hydrogen gas by electrolysis. Hydrogen gas released in this way can be used as hydrogen fuel, or remi ...

. Hydrogen is not a

primary energy Primary energy (PE) is an energy form found in nature that has not been subjected to any human engineered conversion process. It is energy contained in raw fuels, and other forms of energy, including waste, received as input to a system. Prim ...

source Source may refer to: Research * Historical document * Historical source * Source (intelligence) or sub source, typically a confidential provider of non open-source intelligence * Source (journalism), a person, publication, publishing institute o ...

, because it is not naturally occurring as a fuel. It is, however, widely regarded as an ideal energy storage medium, due to the ease with which

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...

can convert water into hydrogen and

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

through electrolysis and can be converted back to electrical power using a fuel cell. There are a wide number of different types of fuel and electrolysis cells. The potential

environmental impact Environmental issues are effects of human activity on the biophysical environment, most often of which are harmful effects that cause environmental degradation. Environmental protection is the practice of protecting the natural environment on t ...

depends primarily on the methods used to generate hydrogen as a fuel.

Fuel cells

Alkaline fuel cell The alkaline fuel cell (AFC), also known as the Bacon fuel cell after its British inventor, Francis Thomas Bacon, is one of the most developed fuel cell technologies. Alkaline fuel cells consume hydrogen and pure oxygen, to produce potable wa ...

(AFC) *

Direct borohydride fuel cell Direct borohydride fuel cells (DBFCs) are a subcategory of alkaline fuel cells which are directly fed by sodium borohydride or potassium borohydride as a fuel and either air/oxygen or hydrogen peroxide as the oxidant. DBFCs are relatively new types ...

(DBFC) *

Direct carbon fuel cell A Direct Carbon Fuel Cell (DCFC) is a fuel cell that uses a carbon rich material as a fuel such as bio-mass or coal. The cell produces energy by combining carbon and oxygen, which releases carbon dioxide as a by-product. It is also called coal fuel ...

(DCFC) *

Direct ethanol fuel cell Direct-ethanol fuel cells or DEFCs are a category of fuel cell in which ethanol is fed directly into the cell. They have been used as a model to investigate a range of fuel cell concepts including the use of PEM. Advantages DEFC uses Ethanol in ...

(DEFC) *

Direct methanol fuel cell Direct-methanol fuel cells or DMFCs are a subcategory of proton-exchange fuel cells in which methanol is used as the fuel. Their main advantage is the ease of transport of methanol, an energy-dense yet reasonably stable liquid at all environmental ...

(DMFC) * Electro-galvanic fuel cell (EGFC) *

Flow battery A flow battery, or redox flow battery (after reduction–oxidation), is a type of electrochemical cell where chemical energy is provided by two chemical components dissolved in liquids that are pumped through the system on separate sides of a ...

(RFC) *

Formic acid fuel cell Formic acid fuel cells (direct formic acid fuel cells or DFAFCs) are a subcategory of direct liquid-feed fuel cells (DLFCs), in which the liquid fuel is directly oxidized (electrochemically) at the anode instead of reforming to produce hydrogen. For ...

(FAFC) *

Metal hydride fuel cell Metal hydride fuel cells are a subclass of alkaline fuel cells that have been under research and development, as well as scaled up successfully in operating systems. A notable feature is their ability to chemically bond and store hydrogen within t ...

(MHFC) *

Microbial fuel cell Microbial fuel cell (MFC) is a type of bioelectrochemical fuel cell system that generates electric current by diverting electrons produced from the microbial oxidation of reduced compounds (also known as fuel or electron donor) on the anode to oxid ...

(MFC) *

Molten carbonate fuel cell Molten-carbonate fuel cells (MCFCs) are high-temperature fuel cells that operate at temperatures of 600 °C and above. Molten carbonate fuel cells (MCFCs) were developed for natural gas, biogas (produced as a result of anaerobic digestion or ...

(MCFC) *

Phosphoric acid fuel cell Phosphoric acid fuel cells (PAFC) are a type of fuel cell that uses liquid phosphoric acid as an electrolyte. They were the first fuel cells to be commercialized. Developed in the mid-1960s and field-tested since the 1970s, they have improved sig ...

(PAFC) * Photoelectrochemical cell (PEC) *

Proton exchange membrane fuel cell A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...

(PEMFC) * Protonic ceramic fuel cell (PCFC) *

Regenerative fuel cell A regenerative fuel cell or reverse fuel cell (RFC) is a fuel cell run in reverse mode, which consumes electricity and chemical B to produce chemical A. By definition, the process of any fuel cell could be reversed. However, a given device is usuall ...

(RFC) *

Solid oxide fuel cell A solid oxide fuel cell (or SOFC) is an electrochemical conversion device that produces electricity directly from oxidizing a fuel. Fuel cells are characterized by their electrolyte material; the SOFC has a solid oxide or ceramic electrolyte. A ...

(SOFC)

Hydrogen infrastructure

*Hydrogen plant ( Steam reformer) *

Hydrogen pipeline transport Hydrogen pipeline transport is a transportation of hydrogen through a pipe as part of the hydrogen infrastructure. History *1938 - Rhine-Ruhr The first hydrogen pipes that are constructed of regular pipe steel, compressed hydrogen pressure , di ...

* Hydrogen pressure letdown station * Compressed hydrogen tube trailer * Liquid hydrogen tank truck * Hydrogen piping *

Hydrogen station A hydrogen station is a storage or filling station for Hydrogen. The hydrogen is dispensed by weight. There are two filling pressures in common use. H70 or 700 bar, and the older standard H35 or 350 bar. As of 2021 around 550 filling stations were ...

* HCNG * Homefueler *

Home Energy Station Home Energy Station is the name of Honda's heat and electricity generator for the home as well as a fuel provider for hydrogen-powered fuel cell vehicles. HES IV is able to supply a sufficient amount of hydrogen to power a fuel cell vehicle, such a ...

* Hydrogen highway * Zero Regio *

Hydrogen compressor A hydrogen compressor is a device that increases the pressure of hydrogen by reducing its volume resulting in compressed hydrogen or liquid hydrogen. Traditionally, applications for hydrogen compressors included Chlorine electrolyser and many che ...

Electrochemical hydrogen compressor An electrochemical hydrogen compressor is a hydrogen compressor where hydrogen is supplied to the anode, and compressed hydrogen is collected at the cathode with an exergy efficiency up to and even beyond 80% for pressures up to 10,000 psi or 700 b ...

Guided rotor compressor The guided-rotor compressor (GRC) is a positive-displacement rotary gas compressor. The compression volume is defined by the trochoidally rotating rotor mounted on an eccentric drive shaft with a typical 80 to 85% adiabatic efficiency. History ...

Hydride compressor A hydride compressor is a hydrogen compressor based on metal hydrides with absorption of hydrogen at low pressure, releasing heat, and desorption of hydrogen at high pressure, absorbing heat, by raising the temperature with an external heat source ...

Ionic liquid piston compressor An ionic liquid piston compressor, ionic compressor or ionic liquid piston pump is a hydrogen compressor based on an ionic liquid piston instead of a metal piston as in a piston-metal diaphragm compressor. Principle An ionic liquid compressor tak ...

Linear compressor A linear compressor is a gas compressor where the piston moves along a linear track to minimize friction and reduce energy loss during conversion of motion. This technology has been successfully used in cryogenic applications which must be oilless ...

Hydrogen turboexpander-generator A hydrogen turboexpander-generator or generator loaded expander for hydrogen gas is an axial flow turbine or radial expander for energy recovery through which a high pressure hydrogen gas is expanded to produce work that is used to drive an electri ...

Hydrogen leak testing Hydrogen leak testing is the normal way in which a hydrogen pressure vessel or installation is checked for leaks or flaw (defect), flaws. This usually involves charging hydrogen as a tracer gas into the device undergoing testing, with any leaking g ...

* Hydrogen sensor * Hydrogen purifier * Hydrogen analyzer * Hydrogen valve

Hydrogen storage

* Compressed hydrogen * Cryo-adsorption *

Liquid hydrogen Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form. To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully l ...

Slush hydrogen Slush hydrogen is a combination of liquid hydrogen and solid hydrogen at the triple point with a lower temperature and a higher density than liquid hydrogen. It is commonly formed by repeating a freeze-thaw process. This is most easily done by bring ...

* Underground hydrogen storage *

Hydrogen tank A hydrogen tank (other names- cartridge or canister) is used for hydrogen storage. The first type IV hydrogen tanks for compressed hydrogen at were demonstrated in 2001, the first fuel cell vehicles on the road with type IV tanks are the Toyota ...

Power to gas Power-to-gas (often abbreviated P2G) is a technology that uses electric power to produce a gaseous fuel. When using surplus power from wind generation, the concept is sometimes called windgas. Most P2G systems use electrolysis to produce hydrogen ...

Hydrogen vehicles

Historic hydrogen filled airships

* Hindenburg (airship) *

Zeppelin A Zeppelin is a type of rigid airship named after the German inventor Count Ferdinand von Zeppelin () who pioneered rigid airship development at the beginning of the 20th century. Zeppelin's notions were first formulated in 1874Eckener 1938, pp ...

Hydrogen powered cars

Audi: * 2004 – Audi A2H2- hybrid vehicle * 2009 –

Audi Q5 The Audi Q5 is a series of compact luxury crossover SUVs produced by the German luxury car manufacturer Audi from 2008. The original first-generation (''Typ 8R'') model was the third member of the ''B8'' family to be released after the Audi A ...

FCEV A fuel cell vehicle (FCV) or fuel cell electric vehicle (FCEV) is an electric vehicle that uses a fuel cell, sometimes in combination with a small battery or supercapacitor, to power its onboard electric motor. Fuel cells in vehicles generate elec ...

BMW: * 2002 – BMW 750hl * 2010 – BMW 1 Series Fuel-cell hybrid electric Chrysler: * 2000 – Jeep Commander II- hybrid vehicle-Commercial * 2001 – Chrysler Natrium- hybrid vehicle * 2003 – Jeep Treo- Fuel cell Daimler: * 1994 – Mercedes-Benz NECAR 1 * 1996 – Mercedes-Benz NECAR 2 * 1997 – Mercedes-Benz NECAR 3 * 1999 – Mercedes-Benz NECAR 4 * 2000 – Mercedes-Benz NECAR 5 * 2002 – Mercedes-Benz F-Cell based on the Mercedes-Benz A-Class * 2005 – Mercedes-Benz F600 Hygenius * 2009 – Mercedes-Benz F-CELL Roadster * 2009 – Mercedes-Benz F-Cell based on the Mercedes-Benz B-Class Fiat: * 2001 – Fiat Seicento Elettra H2 Fuel Cell- hybrid vehicle * 2003 – Fiat Seicento Hydrogen- hybrid vehicle * 2005 –

Fiat Panda Hydrogen The Panda Hydrogen is a prototype fuel cell-type hydrogen vehicle based on the Fiat Panda introduced in 2006. The fuel, gaseous Hydrogen, is stored in underfloor hydrogen tanks at 350 bar. A Nuvera Fuel Cells "Andromeda II" fuel cell stack gen ...

- Fuel cell * 2008 – Fiat Phyllis- Fuel cell * 2008 –

Fiat Panda The Fiat Panda is a city car manufactured and marketed by Fiat since 1980, currently in its third generation. The first generation Panda (Mk 1: 1980–1986 & Mk2: 1986–2003), introduced in 1980, was a two-box, three-door hatchback designed b ...

- Fiat Panda HyTRAN Ford: * 2000 – Ford Focus FCV- Fuel cell. Note however that

Ford Motor Company Ford Motor Company (commonly known as Ford) is an American multinational automobile manufacturer headquartered in Dearborn, Michigan, United States. It was founded by Henry Ford and incorporated on June 16, 1903. The company sells automobi ...

has dropped its plans to develop hydrogen cars, stating that "The next major step in Ford’s plan is to increase over time the volume of electrified vehicles". * 2006 – F-250 Super Chief a ''Tri-Flex engine'' concept pickup. Forze Hydrogen-Electric Racing Team Delft *2016 – Forze- Fuel cell General Motors: * 1966 – GM Electrovan- Fuel cell * 2001 – HydroGen3- Fuel cell * 2002 – GM HyWire- Fuel cell * 2005 – GM Sequel- hybrid vehicle * 2006 – Chevrolet Equinox Fuel Cell * 2007 – HydroGen4 Honda: * 2002 –

Honda FCX The Honda FCX (commonly referred to as ''Fuel Cell eXperimental'') is a family of hydrogen fuel cell automobiles manufactured by Honda. As of March 2007, there are more than twenty Honda FCX vehicles in the hands of customers, including the state ...

– hybrid vehicle * 2007 – Honda FCX Clarity –

Hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

Fuel cell – Production model Hyundai: * 2001 – Hyundai Santa Fe FCEV * 2010 –

Hyundai ix35 FCEV The Hyundai ix35 FCEV or Tucson FCEV is a hydrogen fuel cell electric vehicle developed by Hyundai. The model is a left-hand drive only conversion to the SUV platform it is based on and was the first of its type to be mass-produced and sold comme ...

Lotus Engineering: * 2010 –

Black Cab A hackney or hackney carriage (also called a cab, black cab, hack or London taxi) is a carriage or car for hire. A hackney of a more expensive or high class was called a remise. A symbol of London and Britain, the black taxi is a common s ...

- Fuel cell Kia: * 2009 – Kia Borrego FCEV- Fuel cell Mazda: * 1991 –

Mazda HR-X The Mazda HR-X was the first hydrogen powered concept car produced by Mazda. The car was unveiled at the Tokyo Motor Show in 1991. The car seated four people in a plastic shell and was powered by a two rotor Wankel engine which propelled it to . T ...

Hydrogen Wankel Rotary. * 1993 –

Mazda HR-X2 , commonly referred to as simply Mazda, is a Japanese multinational automotive manufacturer headquartered in Fuchū, Hiroshima, Japan. In 2015, Mazda produced 1.5 million vehicles for global sales, the majority of which (nearly one mi ...

Hydrogen Wankel Rotary. * 1993 – Mazda MX-5 Miata Hydrogen Wankel Rotary. * 1995 – Mazda Capella Cargo, first public street test of the hydrogen Wankel Rotary engine. * 1997 – Mazda Demio FC-EV Methanol-Reducing Fuel Cell * 2001 – Mazda Premacy FC-EV – First public street test of the Methanol-Reducing Fuel Cell vehicle in Japan * 2003 –

Mazda RX-8 Hydrogen RE The Mazda RX-8 Hydrogen RE is a 2003 bi-fuel version of the RX-8 sports car, in which the twin-rotor wankel rotary engine is configured to run on either hydrogen or gasoline. This is the fifth Mazda vehicle to be fitted with a hydrogen wankel r ...

Hydrogen \ Gasoline hybrid Wankel Rotary. * 2007 –

Mazda Premacy Hydrogen RE Hybrid The Mazda Premacy Hydrogen RE Hybrid or Mazda5 Hydrogen RE Hybrid was a hydrogen powered hybrid car produced by Mazda. Later models were also called the Mazda Hydrogen RE Plug in Hybrid. The first car was unveiled in 2005, with an improved version ...

* 2009 – Mazda 5 Hydrogen RE Hybrid Mitsubishi: * 2004 – Mitsubishi FCV Morgan: * 2005 – Morgan LIFEcar- hybrid vehicle-concept car Nissan: * 2002 – Nissan X-Trail FCHV- hybrid vehicle. Note, however that in 2009, Nissan announced that it is cancelling its hydrogen car R&D efforts. Peugeot: * 2004 –

Peugeot Quark The Peugeot Quark was a concept car from Peugeot, rather like a four-wheeled motorcycle or a quad bike. The Quark was first displayed at the 2004 Paris Motor Show and later at the 2005 Amsterdam Motor Show. It utilised hydrogen fuel cells an ...

* 2006 – Peugeot 207 Epure * 2008 – H2Origin- Fuel cell Renault: * Scenic ZEV H2 is a hydro-electric MPV co-developed by Nissan. Riversimple: * 2009 –

Riversimple Urban Car The Riversimple Urban Car is a conceptual open source hydrogen fuel cell vehicle that was proposed by Hugo Spowers' company, Riversimple, in 2009. Their latest model, the Rasa, was unveiled on 17 February 2016. A working prototype vehicle was ...

Ronn Motor Company: * 2008 – Ronn Motor Scorpion Toyota: * 2002 –

Toyota FCHV The Toyota FCHV is a current hybrid hydrogen fuel cell vehicle development programme of the Toyota Motor Corporation, which was leased to a limited number of drivers in the United States and Japan beginning in 2002. "FCHV" stands for "Fuel Ce ...

- hybrid vehicle * 2003 –

Toyota Fine-S is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 m ...

-concept car * 2003 – Toyota Fine-N-concept car * 2005 – Toyota Fine-T-concept car * 2005 – Toyota Fine-X-concept car * 2008 –

Toyota FCHV-adv is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 m ...

-preproduction vehicle (expected public release 2015) Volkswagen: * 2000 – VW Bora Hy-motion- Fuel cell * 2002 – VW Bora Hy-power- Fuel cell * 2004 – VW Touran Hy-motion- Fuel cell * 2007 – VW space up! blue

Hydrogen powered planes

* Hyfish * Smartfish * Tupolev Tu-155-hydrogen-powered version of Tu-154Hydrogen Powered Tupolev Tu-155
Development of Cryogenic Fuel Aircraft, Tupelov * Antares DLR-H2 -The first aircraft capable of performing a complete flight on fuel-cell power only Possible future aircraft using

precooled jet engine The precooled jet engine is a concept that enables jet engines with turbomachinery, as opposed to ramjets, to be used at high speeds. Precooling restores some or all of the performance degradation of the engine compressor (by preventing rotating ...

s include Reaction Engines Skylon and the

Reaction Engines A2 The Reaction Engines Limited LAPCAT Configuration A2 (called the LAPCAT A2) is a design study for a hypersonic speed jet airliner intended to provide, long range, high capacity commercial transportation. The aircraft was designed, ...

Hydrogen powered rockets

The following

rocket A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely fr ...

s were/are partially or completely propelled by hydrogen fuel: *

Saturn V Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, with three stages, and powered with liquid fuel. It was flown from 196 ...

(upper stage) *

Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program ...

* Ariane 5 *

Delta IV Delta IV is a group of five expendable launch systems in the Delta rocket family introduced in the early 2000s. Originally designed by Boeing's Defense, Space and Security division for the Evolved Expendable Launch Vehicle (EELV) program, t ...

Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Mart ...

( Centaur upper stage) * CE-20 (cryogenic rocket engine for upper stage of GSLV-III)

Related technologies

Environmental

Anaerobic digestion Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to Waste management, manage waste or to produce fuels. Mu ...

* Dark fermentation * Photofermentation * Syngas

Nuclear

Generation IV reactor Generation IV reactors (Gen IV) are six nuclear reactor designs recognized by the Generation IV International Forum. The designs target improved safety, sustainability, efficiency, and cost. The most developed Gen IV reactor design is the sodium ...

* Hydrogen bomb

Organic chemistry

Dehydrogenation In chemistry, dehydrogenation is a chemical reaction that involves the removal of hydrogen, usually from an organic molecule. It is the reverse of hydrogenation. Dehydrogenation is important, both as a useful reaction and a serious problem. At ...

Hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organ ...

Hydrogenolysis Hydrogenolysis is a chemical reaction whereby a carbon–carbon or carbon–heteroatom single bond is cleaved or undergoes lysis (breakdown) by hydrogen.Ralph Connor, Homer Adkins. Hydrogenolysis Of Oxygenated Organic Compounds. J. Am. Chem. Soc. ...

Miscellaneous

* Hydrogen odorant * Atomic hydrogen welding * Hydrogen-cooled turbogenerator * Oxyhydrogen flame * Low hydrogen annealing * Hydrogen decrepitation process (HD) * Hydrogenation disproportionation desorption and recombination (HDDR) *

Standard hydrogen electrode The standard hydrogen electrode (abbreviated SHE), is a redox electrode which forms the basis of the thermodynamic scale of oxidation-reduction potentials. Its absolute electrode potential is estimated to be at 25 °C, but to form a basis ...

* Reversible hydrogen electrode * Dynamic hydrogen electrode * Palladium-Hydrogen electrode *

Cathodic protection Cathodic protection (CP; ) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. A simple method of protection connects the metal to be protected to a more easily corroded "sacrific ...

* Iron-hydrogen resistor * Hydrogen pinch * Hofmann voltameter *

Hydrox Hydrox is a cream-filled chocolate sandwich cookie currently owned and manufactured by Leaf Brands. It debuted in the United States in 1908, and was manufactured by Sunshine Biscuits for over 90 years. Hydrox was largely discontinued in 1999, ...

* Hydreliox * Joule-Thomson effect *

Hydrogen ion A hydrogen ion is created when a hydrogen atom loses or gains an electron. A positively charged hydrogen ion (or proton) can readily combine with other particles and therefore is only seen isolated when it is in a gaseous state or a nearly particle ...

Bussard ramjet The Bussard ramjet is a theoretical method of spacecraft propulsion proposed in 1960 by the physicist Robert W. Bussard, popularized by Poul Anderson's novel '' Tau Zero'', Larry Niven in his ''Known Space'' series of books, Vernor Vinge in h ...

Döbereiner's lamp Döbereiner's lamp, also called a "tinderbox" ("Feuerzeug"), is a lighter invented in 1823 by the German chemist Johann Wolfgang Döbereiner. The lighter is based on the Fürstenberger lighter (invented in Basel in 1780; in which hydrogen gas is ...

* Nickel hydrogen battery *

Gas-absorption refrigerator An absorption refrigerator is a refrigerator that uses a heat source (e.g., solar energy, a fossil-fueled flame, waste heat from factories, or district heating systems) to provide the energy needed to drive the cooling process. The system uses t ...

* Electroosmotic pump *

Sodium silicide Sodium silicide (NaSi, Na4Si4) is a binary inorganic compound consisting of sodium and silicon. It is a solid black or grey crystalline material. Sodium silicide reacts readily with water yielding gaseous hydrogen and aqueous sodium silicate in a ...

* Temperature-programmed reduction * Hydrogen damage *

Hydrogen embrittlement Hydrogen embrittlement (HE), also known as hydrogen-assisted cracking or hydrogen-induced cracking (HIC), is a reduction in the ductility of a metal due to absorbed hydrogen. Hydrogen atoms are small and can permeate solid metals. Once absorbed ...

References

{{Environmental technology Hydrogen economy Industrial gases Hydrogenation