1333-74-0

Basic information

• Product Name: Hydrogen
• Synonyms: Dihydrogen;H2;hydrogen,compressed;hydrogen,highpurity;hydrogen,refrigeratedliquid(cryogenicliquid);hydrogengas;Molecular hydrogen;molecularhydrogen
• CAS NO: 1333-74-0
• Molecular Formula: H2
• Molecular Weight: 2.02
• EINECS: 215-605-7
• Product Categories: refrigerants;Inorganics;Chemical Synthesis;Compressed and Liquefied GasesMicro/Nanoelectronics;Electronic Chemicals;Gases;Synthetic Reagents;Compressed and Liquefied Gases;HU - HZGas Standards;Alphabetic;H;Pure Gases;SCOTTY Gases;Hydrogen;Chemical Synthesis;Electronic Chemicals;Materials Science;Micro/NanoElectronics;Specialty Gases;Synthetic Reagents
• Mol File: 1333-74-0.mol
• Article Data: 2245

Chemical Properties

• Melting Point: −259.2 °C(lit.)
• Boiling Point: −252.8 °C(lit.)
• Flash Point: <-150°C
• Appearance: /colorless gas
• Density: 0.0899
• Vapor Density: 0.07 (21 °C, vs air)
• Vapor Pressure: Critical temperature is - 239.9 °C; noncondensible above this temperature
• PKA: 35(at 25℃)
• Explosive Limit: 74.2%
• Water Solubility: 0.00017 g/100 mL
• Stability: Stable. Highly flammable. Readily forms explosive mixtures with air. Upper (U.K.) composition limit for use of a nitrogen/hydrog
• Merck: 13,4813
• CAS DataBase Reference: Hydrogen(CAS DataBase Reference)
• NIST Chemistry Reference: Hydrogen(1333-74-0)
• EPA Substance Registry System: Hydrogen(1333-74-0)

Safety Data

• Hazard Codes: F+
• Statements: 12
• Safety Statements: 9-16-33
• RIDADR: UN 1950 2.1
• RTECS: MW8900000
• F: 4.5-31
• HazardClass: 2.1
• Hazardous Substances Data: 1333-74-0(Hazardous Substances Data)

Usage

Chemical Description

Different sources of media describe the Chemical Description of 1333-74-0 differently. You can refer to the following data:
1. Hydrogen is a chemical element with the symbol H.
2. Hydrogen is a colorless, odorless, and tasteless gas that is the lightest element in the periodic table.
3. Hydrogen and Raney nickel are used for the reduction of nitro compounds to the corresponding amines.
4. Hydrogen and oxygen are gases used to generate radicals in the gas phase, while urea and maleic acid are compounds in the water phase that react with the radicals.

Description

Hydrogen is colorless, odorless, tasteless, flammable, and nontoxic. It exists as a gas at ambient temperatures and atmospheric pressures. It is the lightest gas known, with a density approximately 0.07% that of air. Hydrogen is present in the atmosphere occurring in concentrations of only about 0.5 ppm by volume at lower altitudes.

Chemical Properties

Hydrogen,H2, is a tasteless,colorless, odorless gas that may be liquified by cooling under pressure. Hydrogen is used in welding, in the production of ammonia, methanol, and other chemicals, for the hydrogenation of oil and coal,and for the reduction of metallic oxide ores.It is obtained by the dissociation of water and as a by-product in the electrolysis of brine solutions. Molecular hydrogen at ambient temperature is relatively innocuous to most metals.However, atomic hydrogen is detrimental to most metals.

Physical properties

Hydrogen’s atom is the simplest of all the elements, and the major isotope (H-1) consists ofonly one proton in its nucleus and one electron in its K shell. The density of atomic hydrogenis 0.08988 g/l, and air’s density is 1.0 g/l (grams per liter). Its melting point is –255.34°C,and its boiling point is –252.87°C (absolute zero = –273.13°C or –459.4°F). Hydrogen hastwo oxidation states, +1 and –1.

Isotopes

The major isotope of hydrogen has just one proton and no neutrons in itsnucleus (1H-1).Deuterium (2D or H-2) has a nucleus consisting of one proton plus one neutron. Tritium (3T or H-3), another variety of heavy water (TOT),has nuclei consisting of one proton and two neutrons.

Origin of Name

Hydrogen was named after the Greek term hydro genes, which means “water former.”

History

Hydrogen was prepared many years before it was recognized as a distinct substance by Cavendish in 1766. It was named by Lavoisier. Hydrogen is the most abundant of all elements in the universe, and it is thought that the heavier elements were, and still are, being built from hydrogen and helium. It has been estimated that hydrogen makes up more than 90% of all the atoms or three quarters of the mass of the universe. It is found in the sun and most stars, and plays an important part in the proton– proton reaction and carbon–nitrogen cycle, which accounts for the energy of the sun and stars. It is thought that hydrogen is a major component of the planet Jupiter and that at some depth in the planet’s interior the pressure is so great that solid molecular hydrogen is converted into solid metallic hydrogen. In 1973, it was reported that a group of Russian experimenters may have produced metallic hydrogen at a pressure of 2.8 Mbar. At the transition the density changed from 1.08 to 1.3 g/cm3. Earlier, in 1972, a Livermore (California) group also reported on a similar experiment in which they observed a pressure-volume point centered at 2 Mbar. It has been predicted that metallic hydrogen may be metastable; others have predicted it would be a superconductor at room temperature. On Earth, hydrogen occurs chiefly in combination with oxygen in water, but it is also present in organic matter such as living plants, petroleum, coal, etc. It is present as the free element in the atmosphere, but only to the extent of less than 1 ppm by volume. It is the lightest of all gases, and combines with other elements, sometimes explosively, to form compounds. Great quantities of hydrogen are required commercially for the fixation of nitrogen from the air in the Haber ammonia process and for the hydrogenation of fats and oils. It is also used in large quantities in methanol production, in hydrodealkylation, hydrocracking, and hydrodesulfurization. It is also used as a rocket fuel, for welding, for production of hydrochloric acid, for the reduction of metallic ores, and for filling balloons. The lifting power of 1 ft3 of hydrogen gas is about 0.076 lb at 0°C, 760 mm pressure. Production of hydrogen in the U.S. alone now amounts to about 3 billion cubic feet per year. It is prepared by the action of steam on heated carbon, by decomposition of certain hydrocarbons with heat, by the electrolysis of water, or by the displacement from acids by certain metals. It is also produced by the action of sodium or potassium hydroxide on aluminum. Liquid hydrogen is important in cryogenics and in the study of superconductivity, as its melting point is only a 20°C above absolute zero. Hydrogen consists of three isotopes, most of which is 1H. The ordinary isotope of hydrogen, H, is known as protium. In 1932, Urey announced the discovery of a stable isotope, deuterium (2H or D) with an atomic weight of 2. Deuterium is present in natural hydrogen to the extent of 0.015%. Two years later an unstable isotope, tritium (3H), with an atomic weight of 3 was discovered. Tritium has a half-lifeof about 12.32 years. Tritium atoms are also present in natural hydrogen but in a much smaller proportion. Tritium is readily produced in nuclear reactors and is used in the production of the hydrogen bomb. It is also used as a radioactive agent in making luminous paints, and as a tracer. On August 27, 2001 Russian, French, and Japanese physicists working at the Joint Institute for Nuclear Research near Moscow reported they had made “super-heavy hydrogen,” which had a nucleus with one proton and four neutrons. Using an accelerator, they used a beam of helium-6 nuclei to strike a hydrogen target, which resulted in the occasional production of a hydrogen-5 nucleus plus a helium-2 nucleus. These unstable particles quickly disintegrated. This resulted in two protons from the He-2, a triton, and two neutrons from the H-5 breakup. Deuterium gas is readily available, without permit, at about $1/l.

Characteristics

H2 is a diatomic gas molecule composed of two tightly joined atoms that strongly sharetheir outer electrons. It is an odorless, tasteless, and colorless gas lighter than air. Hydrogenis included in group 1 with the alkali metals because it has an oxidation state of +1 as dothe other alkali metals. Experiments during the 1990s at the Lawrence Livermore NationalLaboratory (LLNL), in Livermore, California, lowered the temperature of H2 to almostabsolute zero. By exploding gunpowder in a long tube that contained gaseous hydrogen, thegas that was under pressure of over one million times the normal atmospheric pressure wascompressed into a liquid. This extreme pressure on the very cold gas converted it to liquidhydrogen (almost to the point of solid metallic hydrogen), in which state it did act as a metaland conduct electricity.Hydrogen gas is slightly soluble in water, alcohol, and ether. Although it is noncorrosive,it can permeate solids better than air. Hydrogen has excellent adsorption capabilities in theway it attaches and holds to the surface of some substances. (Adsorption is not the same asabsorption with a “b,” in which one substance intersperses another.

Uses

Different sources of media describe the Uses of 1333-74-0 differently. You can refer to the following data:
1. Hydrogen is an excellent reducing agent.Production of ammonia (NH3).Ethanol (ethyl alcohol made from grains).Hydrogenation of vegetable oils.
2. Large quantities of hydrogen are produced on site or pipelined for use by refineries, petrochemical and bulk chemical facilities for hydrotreating, catalytic reforming, and hydrocracking. Smaller quantities of hydrogen are produced on site or pipelined for use in the chemical, metallurgical, fats and oils, glass, and electronic industries. Some of these smaller users have hydrogen delivered to their manufacturing location as gaseous hydrogen in cylinders or tube trailers, or by cascade into on-site storage cylinders. Certain smaller users have liquid hydrogen delivered into an on-site liquid hydrogen storage system.
3. In oxy-hydrogen blowpipe (welding) and limelight; autogenous welding of steel and other metals; manufacture of ammonia, synthetic methanol, HCl, NH3; hydrogenation of oils, fats, naphthalene, phenol; in balloons and airships; in metallurgy to reduce oxides to metals; in petroleum refining; in thermonuclear reactions (ionizes to form protons, deuterons (D) or tritons (T)). liquid hydrogen used in bubble chambers to study subatomic particles; as a coolant.

Definition

Different sources of media describe the Definition of 1333-74-0 differently. You can refer to the following data:
1. hydrogen: Symbol H. A colourlessodourless gaseous chemical element;a.n. 1; r.a.m. 1.008; d. 0.0899 g dm–3;m.p. –259.14°C; b.p. –252.87°C. It isthe lightest element and the mostabundant in the universe. It is presentin water and in all organic compounds.There are three isotopes:naturally occurring hydrogen consistsof the two stable isotopes hydrogen–1 (99.985%) and deuterium. Theradioactive tritium is made artificially.The gas is diatomic and hastwo forms: orthohydrogen, in whichthe nuclear spins are parallel, andparahydrogen, in which they are antiparallel.At normal temperaturesthe gas is 25% parahydrogen. In theliquid it is 99.8% parahydrogen. Themain source of hydrogen is steamreforming of natural gas. It can alsobe made by the Bosch process (seehaber process) and by electrolysis ofwater. The main use is in the Haberprocess for making ammonia. Hydrogenis also used in various other industrial processes, such as thereduction of oxide ores, the refiningof petroleum, the production ofhydrocarbons from coal, and the hydrogenationof vegetable oils. Considerableinterest has also been shownin its potential use in a ‘hydrogenfuel economy’ in which primary energysources not based on fossil fuels(e.g. nuclear, solar, or geothermal energy)are used to produce electricity,which is employed in electrolysingwater. The hydrogen formed isstored as liquid hydrogen or as metalhydrides. Chemically, hydrogen reactswith most elements. It was discoveredby Henry Cavendish in1766.
2. ChEBI: An elemental molecule consisting of two hydrogens joined by a single bond.

Production Methods

Hydrogen gas may be produced by several methods. It is commerciallyobtained by electrolysis of water. It also is made industrially by the reactionof steam with methane or coke: CH4 + H2O → CO + 3H2 C + H2O → CO + H2 CO + H2O → CO2 + H2 The reactions are carried out at about 900 to 1,000°C and catalyzed by nick-el, nickel-alumina, or rhodium-alimina catalysts. In the laboratory, hydrogenmay be prepared by the reaction of zinc or iron with dilute hydrochloric or sulfuric acid: Zn + 2HCl → ZnCl2 + H2 It also may be prepared by passing water vapor over heated iron: H2O + Fe → FeO + H2 Also, it can be generated by reaction of metal hydrides with water: CaH2 + 2H2O → Ca(OH)2 + 2H2 Another method of preparation involves heating aluminum, zinc, or otheractive metals in dilute sodium hydroxide or potassium hydroxide: 2Al + 6NaOH → 2Na3AlO3 + 3H2 Zn + 2KOH → K2ZnO2 + H2

General Description

Hydrogen is a colorless, odorless gas. Hydrogen is easily ignited. Once ignited Hydrogen burns with a pale blue, almost invisible flame. The vapors are lighter than air. Hydrogen is flammable over a wide range of vapor/air concentrations. Hydrogen is not toxic but is a simple asphyxiate by the displacement of oxygen in the air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. Hydrogen is used to make other chemicals and in oxyHydrogen welding and cutting.

Air & Water Reactions

Highly flammable.

Reactivity Profile

Finely divided platinum and some other metals will cause a mixture of Hydrogen and oxygen to explode at ordinary temperatures. If a jet of Hydrogen in air impinges on platinum black the metal surface gets hot enough to ignite the gases, [Mellor 1:325(1946-1947)]. Explosive reactions occur upon ignition of mixtures of nitrogen trifluoride with good reducing agents such as ammonia, Hydrogen, Hydrogen sulfide or methane. Mixtures of Hydrogen, carbon monoxide, or methane and oxygen difluoride are exploded when a spark is discharged, [Mellor 2, Supp. 1:192(1956)]. An explosion occurred upon heating 1'-pentol and 1''-pentol under Hydrogen pressure. Hydrogen appears that this acetylenic compound under certain conditions suddenly breaks down to form elemental carbon, Hydrogen, and carbon monoxide with the release of sufficient energy to develop pressures in excess of 1000 atmospheres, [AIChE Loss Prevention, p1, (1967)].

Hazard

Different sources of media describe the Hazard of 1333-74-0 differently. You can refer to the following data:
1. Highly flammable and explosive, dangerous when exposed to heat or flame, explosive limits in air 4–75% by volume.
2. Hydrogen gas is very explosive when mixed with oxygen gas and touched off by a spark or flame. Many hydrides of hydrogen are dangerous and can become explosive if not stored and handled correctly. Many organic and hydrocarbon compounds are essential for life to exist, but just as many are poisonous, carcinogenic, or toxic to living organisms.

Health Hazard

Different sources of media describe the Health Hazard of 1333-74-0 differently. You can refer to the following data:
1. Vapors may cause dizziness or asphyxiation without warning. Some may be irritating if inhaled at high concentrations. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire may produce irritating and/or toxic gases.
2. Hydrogen is practically nontoxic. In high concentrations this gas is a simple asphyxiant, and ultimate loss of consciousness may occur when oxygen

Fire Hazard

Different sources of media describe the Fire Hazard of 1333-74-0 differently. You can refer to the following data:
1. EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air. Vapors from liquefied gas are initially heavier than air and spread along ground. CAUTION: Hydrogen (UN1049), Deuterium (UN1957), Hydrogen, refrigerated liquid (UN1966) and Methane (UN1971) are lighter than air and will rise. Hydrogen and Deuterium fires are difficult to detect since they burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.) Vapors may travel to source of ignition and flash back. Cylinders exposed to fire may vent and release flammable gas through pressure relief devices. Containers may explode when heated. Ruptured cylinders may rocket.
2. Hydrogen is a highly flammable gas that burns with an almost invisible flame and low heat radiation. Hydrogen forms explosive mixtures with air from 4 to 75% by volume. These explosive mixtures of hydrogen with air (or oxygen) can be ignited by a number of finely divided metals (such as common hydrogenation catalysts). In the event of fire, shut off the flow of gas and extinguish with carbon dioxide, dry chemical, or halon extinguishers. Warming of liquid hydrogen contained in an

Flammability and Explosibility

Hydrogen is a highly flammable gas that burns with an almost invisible flame and low heat radiation. Hydrogen forms explosive mixtures with air from 4 to 75% by volume. These explosive mixtures of hydrogen with air (or oxygen) can be ignited by a number of finely divided metals (such as common hydrogenation catalysts). In the event of fire, shut off the flow of gas and extinguish with carbon dioxide, dry chemical, or halon extinguishers. Warming of liquid hydrogen contained in an enclosed vessel to above its critical temperature can cause bursting of that container.

Agricultural Uses

Hydrogen, a non-metallic element, is a colorless odorless, tasteless gas occurring in water combined with oxygen, and in all organic compounds (for example, hydrocarbons and carbohydrates). It is produced by electrolysis of water and is used in the Haber-Bosch process for producing ammonia - a major raw material for nitrogenous fertilizers.Large quantities of hydrogen are utilized in catalytic hydrogenation of unsaturated vegetable oils to make solid fats and petroleum refining. Large quantities of hydrogen are also used as a propulsion fuel for rockets in conjunction with oxygen or fluorine. Being flammable, it is used with helium for filling balloons and airships.Hydrogen is the lightest of all the elements holding position in Group 1 of the Periodic Table. It is abundant in the universe. There are three hydrogen isotopes namely hydrogen- 1, deuterium and tritium. The first two are naturally occurring stable isotopes and the third being radioactive, is made artificially.

Materials Uses

Hydrogen gas is noncorrosive and may be contained at ambient temperatures by most common metals used in installations designed to have sufficient strength for the working pressures involved. Equipment and piping built to use hydrogen should be selected with consideration of the possibility of embrittlement, particularly at elevated pressures and temperatures above 450°F (232°C). A Nelson curve should be consulted to select the proper alloys. Metals used for liquid hydrogen equipment must have satisfactory properties at very low operating temperatures. Ordinary carbon steels lose their ductility at liquid hydrogen temperatures and are considered too brittle for this service. Suitable materials include austenitic chromium-nickel steels (stainless steels), copper, copper silicon alloys, aluminum, Monel, and some brasses and bronzes.

Physiological effects

Hydrogen is nontoxic, but it can act as a simple asphyxiant by displacing or diluting atmospheric air to the point where the oxygen content cannot support life. Unconsciousness without any warning symptoms can occur from inhaling air that contains a sufficiently large amount of hydrogen.

storage

hydrogen cylinders should be clamped or otherwise supported in place and used only in areas free of ignition sources and separate from oxidizers. Expansion of hydrogen released rapidly from a compressed cylinder will cause evolution of heat due to its negative Joule-Thompson coefficient.

Purification Methods

It is usually purified by passing through a suitable absorption train of tubes. Carbon dioxide is removed with KOH pellets, soda-lime or NaOH pellets. Oxygen is removed with a “De-oxo” unit or by passage over Cu heated to 450-500o and Cu on Kieselguhr at 250o. Passage over a mixture of MnO2 and CuO (Hopcalite) oxidises any CO to CO2 (which is removed as above). Hydrogen can be dried by passage through dried silica-alumina at -195o, through a dry-ice trap followed by a liquid-N2 trap packed with glass wool, through CaCl2 tubes, or through Mg(ClO4)2 or P2O5. Other purification steps include passage through a hot palladium thimble [Masson J Am Chem Soc 74 4731 1952], through an activated-charcoal trap at -195o, and through a non-absorbent cotton-wool filter or small glass spheres coated with a thin layer of silicone grease. Potentially VERY EXPLOSIVE in air.

Incompatibilities

Hydrogen is a reducing agent and reacts explosively with strong oxidizers such as halogens (fluorine, chlorine, bromine, iodine) and interhalogen compounds.

Waste Disposal

Excess hydrogen cylinders should be returned to the vendor. Excess hydrogen gas present over reaction mixtures should be carefully vented to the atmosphere under conditions of good ventilation after all ignition sources have been removed. For more information on disposal procedures, see Chapter 7 of this volume.

GRADES AVAILABLE

CGA G-5.3, Commodity Specification for Hydrogen, presents the component maxima in parts per million (v/v), unless shown otherwise, for the types and grades of hydrogen [1]. These are also known as quality verification levels (QVLs). Gaseous hydrogen is denoted as Type I, and liquefied hydrogen as Type II in the table. A blank indicates no maximum limiting characteristics are specified.

InChI:InChI=1/H2/h1H/i1+0H

Synthetic route

water (7732-18-5) → hydrogen (1333-74-0)

Conditions	Yield
With aluminium; sodium hydroxide at 21℃; under 758 Torr; Product distribution / selectivity; Sealed tube;	100%
With Ce0896Y0.05Nb0054O2 at 1499.84℃; under 0.00750075 Torr; Reagent/catalyst;	100%
With bis(pentamethylcyclopentadienyl)iron(II); Mn(bpy)2Br2 In acetonitrile for 22h; Catalytic behavior; Reagent/catalyst; Inert atmosphere; Sealed tube;	100%

methanol (67-56-1) → carbon dioxide (124-38-9) + hydrogen (1333-74-0)

Conditions	Yield
With water at 20℃; pH=4.5; Quantum yield; UV-irradiation; Inert atmosphere;	A n/a B 100%
With water at 350℃; Catalytic behavior; Temperature; Flow reactor;	A n/a B 14%
With catalyst: TiO2/2percent-wt Pt In neat (no solvent) byproducts: formaldehyde; Irradiation (UV/VIS); photolysis (500 W Xe-lamp 350 and 400 nm, 25°C); IR spectroscopy, gas chromy.;

formic acid (64-18-6) → carbon dioxide (124-38-9) + hydrogen (1333-74-0)

Conditions	Yield
With sodium formate at 20℃; Catalytic behavior; Green chemistry; chemoselective reaction;	A n/a B 100%
With [pentamethylcyclopentadienyl*Ir(2,2′-bpyO)(OH)][Na] In water at 80℃; for 1h; Reagent/catalyst;	A n/a B 99%
With (1,2,3,4,5-pentamethylcyclopentadienyl)Ir[κ2(N,N’)-(S,S)-N-triflyl-1,2-diphenylethylenediamine] In 1,2-dimethoxyethane; water at 0℃; for 53h; Reagent/catalyst; Time; Temperature; Solvent;	A n/a B 85%

indium (7440-74-6) + water (7732-18-5) → hydrogen (1333-74-0)

Conditions	Yield
byproducts: In2O3; at 473°K and then at 673-773°K more;	100%

caesium hydride → hydrogen (1333-74-0)

Conditions	Yield
vacuum, below 300°C;	100%
In neat (no solvent) discoloration of CsH under influence of glow discharge with formation of H2;;
In neat (no solvent) discoloration of CsH under influence of glow discharge with formation of H2;;

rubidium hydride → hydrogen (1333-74-0)

Conditions	Yield
vacuum, below 300°C;	100%
In neat (no solvent) influence of glow discharge;;
In neat (no solvent) influence of glow discharge;;

acetic acid (64-19-7) → hydrogen (1333-74-0)

Conditions	Yield
Fe(I)2[μ-SCH2CH2OCH2CH2S-μ](CO)6 In tetrahydrofuran Electrolysis; under N2; electrolysis of MeCN soln. of Fe complex contg. CH3COOH at 2.30 V; detd. by chromatographic analysis;	100%
[Fe(I)2(CO)6(μ-S-N,N-bis(thiomethyl)-p-methoxyaniline)] In acetonitrile Kinetics; Electrolysis; at -2.18 V (vs. Fc/Fc(+));	90%
With tetra-n-butylammonium hexafluorophosphate; [CH3C(O)SCH2C(O)N(CH2SFe(CO)3)2] In acetonitrile Kinetics; Electrolysis; at -2.34 V (Fc/Fc(+)) for 0.5 h; gas chromy.;	90%

[Fe(μ-S2(CH2)3)(CN)(CO)4(PMe3)](1-) (392334-61-1, 371241-08-6, 392333-87-8, 1226500-22-6) + sulfuric acid (7664-93-9) → hydrogen (1333-74-0)

Conditions	Yield
In water Electrolysis; electrolysis of soln. of Fe2(CO)4(CN)(PMe3)S2(CH2)3 with 50 equiv. H2SO4at -1.2 V for 15 min; GC analysis;	100%

vanadium sulfate → hydrogen (1333-74-0) + sulfur (7704-34-9)

Conditions	Yield
1690°C complete decompn.;	A 100% B n/a
red heat;	A 7% B n/a
400°C;

trifluoroacetic acid (76-05-1) → hydrogen (1333-74-0)

Conditions	Yield
With potassium hexafluorophosphate; C27H29BrN5Pd(1+)*BF4(1-); tert-butylammonium hexafluorophosphate(V) In N,N-dimethyl-formamide Electrochemical reaction;	100%
With [Mn(2,2’-bipyridine)3]+[(CO)3Mn(μ-phenylsulfide)3Mn(CO)3]- In acetonitrile Catalytic behavior; Mechanism; Electrolysis;	95%
With [(cis-C2H2(PPh2)2)Ni(μ-H)(μ-S2C3H6)Fe(CO)(cis-C2H2(PPh2)2)]BF4 In acetonitrile Catalytic behavior; Inert atmosphere; Schlenk technique; Electrolysis;	93%

ammonia (7664-41-7) → hydrogen (1333-74-0)

Conditions	Yield
byproducts: N2; red heat;	100%
decompn., heated porcelain pipe, 1100.degreeC;	75.7%
With catalyst: Ru/SiC In gas Kinetics; byproducts: N2; NH3 decompd. in integrated ceramic microreactor at 450-1000°C; analyzed by gas chromatograph (Porapak N, TCD detector);

hydrogen iodide (10034-85-2) → hydrogen (1333-74-0) + iodine (7553-56-2)

Conditions	Yield
Kinetics; Irradiation (UV/VIS); in glass vessel or uviol vessel, wavelenght higher than 2540Å;;	A 100% B 100%
Kinetics; Irradiation (UV/VIS); at room temperature, in quartz vessel; equilibrium; wavelenght lower than 2540Å;;	A 92.3% B 92.3%
995 °C; part of a Mg-S-I water splitting cycle;	A 31% B 31%

tripotassiumdecaisobutylpentaaluminum + hydrogen cation → Isobutane (75-28-5) + potassium ion + hydrogen (1333-74-0) + Al(OH)2(1+)

Conditions	Yield
With water In water acid hydrolysis with 20% HCl; quantities of the products determined;	A n/a B 100% C n/a D n/a

LaFe(1+) (111496-23-2) + cyclohexane (110-82-7) → LaFeC6H6(1+) + hydrogen (1333-74-0)

Conditions	Yield
In gas reaction in a mass spectrometer; total pressure: 4E-6 Torr;	A 100% B 100%

ammonia borane complex (10043-11-5) → hydrogen (1333-74-0)

Conditions	Yield
With [IrH2{(P(phenyl)2(o-C6H4CO))2H}] In tetrahydrofuran; water at 30℃; under 760.051 Torr; for 0.533333h; Catalytic behavior; Kinetics; Reagent/catalyst;	100%
In neat (no solvent) at 50°C;;	1.5%
With dihydrogen hexachloroplatinate In neat (no solvent) thermal decomposition of NH3BH3 milled with hydrogen hexachloroplatinate(IV) hydrate;

LaFe(1+) (111496-23-2) + propane (74-98-6) → LaFeC3H6(1+) + hydrogen (1333-74-0)

Conditions	Yield
In gas reaction in a mass spectrometer; sample pressure 4E-7 Torr;	A 100% B 100%

(triphos)RhH3 (100333-94-6) → [(CH3C(CH2PPh2)3)Rh(CO)(H)] (124223-20-7, 101075-59-6) + hydrogen (1333-74-0)

Conditions	Yield
With CO In dichloromethane-d2 Charging of a soln. of Rh-complex with CO (1 atm), soln. turns immediately bright yellow.; Monitored by (1)H-NMR.;	A 100% B n/a

methanol (67-56-1) + {{(C5H5)2Y(μ-H)}3(μ3-H)}(1-)*Li(THF)4(1+) (90762-81-5) → {{(C5H5)2Y(μ-OCH3)}3(μ3-H)}(1-)*{Li(THF)4}(1+) (111409-63-3) + hydrogen (1333-74-0)

Conditions	Yield
In tetrahydrofuran under inert gas; Y compound in THF and 3 equiv CH3OH combined at -195.8°C; warming to -78°C and stirring for 1.5 h; warming to room temp.; evapn. of the solvent; Y complex pptd. with toluene and centrifugated; chem. anal.;	A 100% B 100%

methanol (67-56-1) + {{(C5H5)2Y(μ-H)}3(μ3-H)}(1-)*Li(THF)4(1+) (90762-81-5) → {{(C5H5)2Y(μ-H)}{(C5H5)2Y(OCH3)}2(μ3-H)}(1-)*{Li(THF)4}(1+) (111435-10-0) + hydrogen (1333-74-0)

Conditions	Yield
In tetrahydrofuran under inert gas; Y compound in THF and 2 equiv CH3OH combined at -195.8°C; warming to -78°C and stirring for 1.5 h; warming to room temp.; evapn. of the solvent; Y complex pptd. with toluene and centrifugated; chem. anal.;	A 100% B 100%

methanol (67-56-1) + {{(C5H5)2Y(μ-H)}3(μ3-H)}(1-)*Li(THF)4(1+) (90762-81-5) → {{(C5H5)2Y(μ-H)}2{(C5H5)2Y(μ-OCH3)}(μ3-H)}(1-)*{Li(THF)4}(1+) (111435-08-6) + hydrogen (1333-74-0)

Conditions	Yield
In tetrahydrofuran under inert gas; equiv. amts. of the Y compound in THF and CH3OH combined at -195.8°C; warming to -78°C and stirring for 1.5 h; warming to room temp.; evapn. of the solvent; Y complex pptd. with toluene and centrifugated; chem. anal.;	A 100% B 100%

methanol (67-56-1) + {{(C5H5)2Y(μ-H)}2{(C5H5)2Y(μ-OCH3)}(μ3-H)}(1-)*{Li(THF)4}(1+) (111435-08-6) → {{(C5H5)2Y(μ-H)}{(C5H5)2Y(OCH3)}2(μ3-H)}(1-)*{Li(THF)4}(1+) (111435-10-0) + hydrogen (1333-74-0)

Conditions	Yield
In tetrahydrofuran under inert gas; equiv. amts of the Y compound in THF and CH3OH combined at -195.8°C; warming to -78°C and stirring for 1.5 h; warming to room temp.; evapn. of the solvent; Y complex pptd. with toluene and centrifugated; chem. anal.;	A 100% B 100%

LaFe(1+) (111496-23-2) + 2,3-dimethylbutane (79-29-8) → LaFeC6H10(1+) + hydrogen (1333-74-0)

Conditions	Yield
In gas reaction in a mass spectrometer; total pressure: 4E-6 Torr;	A 100% B 100%

LaFe(1+) (111496-23-2) + methyl cyclohexane (82166-21-0) → LaFeC7H8(1+) + hydrogen (1333-74-0)

Conditions	Yield
In gas reaction in a mass spectrometer; total pressure: 4E-6 Torr;	A 100% B 100%

(η(5):η(5)-fulvalene)Mo2(CO)6(H)2 → (η(5):η(5)-fulvalene)Mo2(CO)6 + hydrogen (1333-74-0)

Conditions	Yield
In tetrahydrofuran under N2, degassed soln. of ((C5H4)2)Mo2(CO)6H2 in THF kept at 20°C for 24 h; H2 detected by MS; soln. rotary evapd., filtered through alumina using acetone;	A 100% B n/a

5(CH3CH2)4N(1+)*Mo2Fe6S8(S(C6H5))9(5-)=((CH3CH2)4N)5Mo2Fe6S8(S(C6H5))9 + thiophenol (108-98-5) → {MoFe}(3-) + hydrogen (1333-74-0)

Conditions	Yield
In N,N-dimethyl acetamide Kinetics; byproducts: Et4NSPh; under argon, to complex in DMA soln. of PhSH in DMA (500 equiv) was added, 25°C, 24 h, various yields of products for various ratios of educts; PhSSPh in DMA was added, products were not isolated;	A n/a B 100%
In acetonitrile Kinetics; byproducts: Et4NSPh; under argon, to complex in DMA soln. of PhSH in MeCN (1/1 molar ratio) was added, 25°C, 24 h, various yields of products for various ratios of educts; products were not isolated;	A n/a B 10%
In N,N-dimethyl acetamide byproducts: C6H5S(1-); Ar, excess PhSH; UV;	A n/a B >99

N-tert-butylaminoborane (7337-45-3) → hydrogen (1333-74-0)

Conditions	Yield
With [IrH2{(P(phenyl)2(o-C6H4CO))2H}] In tetrahydrofuran; water Catalytic behavior; Kinetics; Thermodynamic data; Reagent/catalyst;	100%
120-140°C;;
In neat (no solvent) at 10-15°C;

(biphenyl){Cr(CO)2}2(μ-dimethylphosphinomethane) (90502-53-7) + trifluorormethanesulfonic acid (1493-13-6) → hydrogen (1333-74-0)

Conditions	Yield
under N2, high vac. line, swivel side arm is charged with acid (degassed), sample of metal complex is placed in the react. flask, acid is poured onto the complex (27°C), react. for 10 min; MS;	100%

(PPh3)3CoH(N2) (21373-88-6, 16920-54-0) + 2,2,2-trifluoroethyl benzoate (1579-72-2) → (trifluoroethoxo)tris(triphenylphosphine)cobalt(I) (99668-73-2) + benzoic acid benzyl ester (120-51-4) + nitrogen (7727-37-9) + hydrogen (1333-74-0) + benzene (71-43-2)

Conditions	Yield
In toluene PhCOOCH2CF3 added to toluene soln. of CoH(N2)(PPh3)3, evacuated, stirred at 20°C for 2 days;	A n/a B 28% C 100% D 17% E 32%

bis[bis(trimethylsilyl)amido][[(trimethylsilyl)methyl]stannyl]praseodymium*0.5(dimethoxyethane) → chloro-trimethyl-silane (75-77-4) + hydrogen (1333-74-0) + praseodymium(III) chloride (10361-79-2) + Chlor-tris<(trimethylsilyl)methyl>zinn (34570-67-7) + 1,1,1,3,3,3-hexamethyl-disilazane (999-97-3)

Conditions	Yield
With hydrogenchloride In tetrahydrofuran mixt. od dry HCl (excess), Pr/Sn-complex and THF keeping dor 1 d at room temp., THF replacing by hexane in usual way; ppt. filtration of, hexane-soln. evapn. (vac.), residue crystn. twice (hexane, -70°C), GLC of volatiles;	A 50% B 87% C 100% D 76.2% E 33.3%

18-crown-6 ether (17455-13-9) + nido-NB10H13 + potassium triethylborohydride → bis[(18-crown-6)potassium][undecahydro-7-aza-nido-undecaborate] + hydrogen (1333-74-0)

Conditions	Yield
In tetrahydrofuran byproducts: BEt3; molar ratio NB10H13:KBHEt3 1:2, cooling (-78°C), stirring (2 h, room temp.); evapn. (vac.), dissoln. (THF), crystn. (-40°C), recrystn. (CH3CN); elem. anal.;	A 23% B 100%

hydrogen (1333-74-0) + oxygen (80937-33-3) → water (7732-18-5)

Conditions	Yield
platinum In neat (no solvent) reaction at room temperature;;	100%
platinum In neat (no solvent) reaction at room temperature;;	100%
alpha-alumina impergnated with patinum nitrate and tin (II) chloride calcinated at 500C (0.08 wtpercent Pt; 0.08 wtpercent Sn) at 300℃; under 9000.9 Torr; Conversion of starting material; Gas phase;

hydrogen (1333-74-0) + cadmium(II) oxide → cadmium (7440-43-9)

Conditions	Yield
3h at 290-300°C, flowing hydrogen, react. start even at 282°C;	100%
below temp. of sintering;

sulfur dioxide (7446-09-5) + hydrogen (1333-74-0) → disulfur (23550-45-0) + hydrogen sulfide (7783-06-4)

Conditions	Yield
In neat (no solvent) byproducts: H2O; redn. of SO2 by H2 (1:2), SO2-conversion at 114°C practically 100%;;	A 100% B n/a
In neat (no solvent) byproducts: H2O; redn. of SO2 by H2 (1:2), SO2-conversion at 114°C practically 100%;;	A 100% B n/a
In neat (no solvent) byproducts: H2O; redn. of SO2 by H2, investigation of equilibrium constants;;

goethite + hydrogen (1333-74-0) → iron (7439-89-6)

Conditions	Yield
In neat (no solvent) Isothermal heat treatment for 2 h at 400°C.;	100%

hydrogen (1333-74-0) + acetonitrile (75-05-8) → hydrogen cyanide (74-90-8)

Conditions	Yield
In gas 600-850°C;	100%
with H atom;
With catalyst: 19percent Cr2O3/Al2O3 byproducts: methane; react. at 875 K; monitored by gas chromy.;

[Ru(H)(Cl)(tris(m-sulfonatophenyl)phosphine)3] + Na(1+)*{BH4}(1-)*99H2O=Na{BH4}*99H2O + hydrogen (1333-74-0) + tris-(m-sulfonatophenyl)phosphine (91171-35-6) → [RuH2(tris(sulfonatophenyl)phosphine)4]*NaCl

Conditions	Yield
In water (Ar); slow H2 bubbling through Ru- and org.-compd. soln. with stirring (room temp., 10 min), NaBH4 addn.; cooling, evapn. to dryness, drying (vac., 2 h, 50°C);	100%

[Ru(Cl)(μ-Cl)(tris(m-sulfonatophenyl)phosphine)2]2 + Na(1+)*{BH4}(1-)*99H2O=Na{BH4}*99H2O + hydrogen (1333-74-0) + tris-(m-sulfonatophenyl)phosphine (91171-35-6) → [RuH2(tris(sulfonatophenyl)phosphine)4]*2NaCl

Conditions	Yield
In water (Ar); slow H2 bubbling through Ru- and org.-compd. soln. with stirring (room temp., 10 min), NaBH4 addn.; cooling, evapn. to dryness, drying (vac., 2 h, 50°C);	100%

hydrogen (1333-74-0) → arsenic (7440-38-2, 460345-38-4)

Conditions	Yield
from As soln. with hydrogen developed on cathode;	100%
from As soln. with hydrogen developed on cathode;	100%

(triphos)RhH3 (100333-94-6) + hydrogen (1333-74-0) → [(CH3C(CH2PPh2)3)Rh(CO)(H)] (124223-20-7, 101075-59-6)

Conditions	Yield
With CO In benzene-d6 High Pressure; Charging of Rh-complex soln. with CO/H2 (500 psi), heating in a high-pressure react. vessel for 4.5 h at 75°C.; Monitored by (1)H-NMR.;	100%
With CO In benzene-d6 Charging of Rh-complex soln. with CO/H2 (1 atm).; Monitored by (1)H-NMR.;	100%

FeRu(CO)6(σ-N,μ2-N`,η2-C=N`-1,4-di-isopropyl-1,4-diaza-1,3-butadiene) (90219-33-3) + hydrogen (1333-74-0) → 1,2-ethanediylbis(isopropylamido)hexacarbonylironruthenium

Conditions	Yield
In dichloromethane-d2 Kinetics; soln. was pressurized with H2; conversion was monitored by 1H NMR;	100%

Upstream product

• 34557-54-5 methane 
• 16940-66-2 sodium tetrahydroborate 
• 7553-56-2 iodine 
• 9005-25-8 starch 
• 7440-44-0 pyrographite 
• 56-81-5 glycerol 
• 7732-18-5 water 
• 124-38-9 carbon dioxide 
• 80937-33-3 oxygen 
• 67-56-1 methanol 
• 74-84-0 ethane 
• 74-98-6 propane 
• 201230-82-2 carbon monoxide 
• 7440-66-6 zinc 

Downstream Products

• 34557-54-5 methane 
• 124-38-9 carbon dioxide 
• 201230-82-2 carbon monoxide 
• 10124-31-9 ammonium dihydrogen phosphate 
• 821-09-0 n-Pent-4-enyl alcohol 
• 39161-19-8 pent-3-en-1-ol 
• 106592-90-9 4-Hydroxy-6-methyl-3-(1'-phenyl-propyl)-2-pyrone 
• 177351-83-6 1,3-bis(cyclohexylmethyl)-5,6-diaminouracil 
• 92016-97-2 α-(2'-hydroxybenzyl)-γ-butyrolactone 
• 24176-70-3 4-[(methylsulfonyl)methyl]aniline 
• 330478-88-1 methyl-2-methyl-4-benzylamino-6{2-[1-(3α,7α,12α-trihydroxy-10β,13β-dimethyl-17β-(carboxy-1-methylpropyl)hexadecahydrocyclopenta[a]phenantren-3-yl)eth-1yl]}quinoline-3-carboxylate 
• 157284-74-7 2-(4-hydroxy-benzyl)-malonic acid dimethyl ester 
• 359714-43-5 5-methoxy-3-(4-amino-3-methylphenyl)-3H-(1,3,4)oxadiazol-2-one 
• 359714-44-6 5-methoxy-3-(4-amino-3-(4-fluorobenzyloxy)phenyl)-3H-(1,3,4)oxadiazol-2-one 

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Gas Reactions of Carbon

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Trans-(Cl)-[Ru(5,5′-diamide-2,2′-bipyridine)(CO)2Cl2]: Synthesis, Structure, and Photocatalytic CO2 Reduction Activity

A series of trans-(Cl)-[Ru(L)(CO)2Cl2]-type complexes, in which the ligands L are 2,2′-bipyridyl derivatives with amide groups at the 5,5′-positions, are synthesized. The C-connected amide group bound to the bipyridyl ligand through

Capacity enhancement of aqueous borohydride fuels for hydrogen storage in liquids

Abstract In this work we demonstrate enhanced hydrogen storage capacities through increased solubility of sodium borate product species in aqueous media achieved by adjusting the sodium (NaOH) to boron (B(OH)3) ratio, i.e., M/B, to obtain a distribution of polyborate anions. For a 1:1 mol ratio of NaOH to B(OH)3, M/B = 1, the ratio of the hydrolysis product formed from NaBH4 hydrolysis, the sole borate species formed and observed by 11B NMR is sodium metaborate, NaB(OH)4. When the ratio is 1:3 NaOH to B(OH)3, M/B = 0.33, a mixture of borate anions is formed and observed as a broad peak in the 11B NMR spectrum. The complex polyborate mixture yields a metastable solution that is difficult to crystallize. Given the enhanced solubility of the polyborate mixture formed when M/B = 0.33 it should follow that the hydrolysis of sodium octahydrotriborate, NaB3H8, can provide a greater storage capacity of hydrogen for fuel cell applications compared to sodium borohydride while maintaining a single phase. Accordingly, the hydrolysis of a 23 wt.% NaB3H8 solution in water yields a solution having the same complex polyborate mixture as formed by mixing a 1:3 M ratio of NaOH and B(OH)3 and releases >8 eq of H2. By optimizing the M/B ratio a complex mixture of soluble products, including B3O3(OH)52-, B4O5(OH)42-, B3O3(OH)4-, B5O6(OH)4- and B(OH)3, can be maintained as a single liquid phase throughout the hydrogen release process. Consequently, hydrolysis of NaB3H8 can provide a 40% increase in H2 storage density compared to the hydrolysis of NaBH4 given the decreased solubility of sodium metaborate.

Immobilizing cobalt phthalocyanine into a porous carbonized wood membrane as a self-supported heterogenous electrode for selective and stable CO2electroreduction in water

Immobilizing a cobalt phthalocyanine (CoPc) molecular electrocatalyst into a porous carbonized wood membrane (CoPc/CWM) results in a self-supported heterogenous electrode. The CoPc/CWM electrode with an ultralow CoPc loading of 8.2 × 10-6 mol cm-2 exhibits a faradaic efficiency (FE) over 90% for CO production at a wide potential range from-0.59 to-0.78 V versus reversible hydrogen electrode (RHE) and excellent long-term durability during a 12 h electrolysis reaction. This journal is

Carbon quantum dot sensitized integrated Fe2O3@g-C3N4 core-shell nanoarray photoanode towards highly efficient water oxidation

The construction of integrated heterojunction system photoelectrodes for solar energy conversion is indubitably an efficient alternative due to their effectiveness in charge separation and optimizing the ability for reduction and oxidation reactions. Here, an integrated photoanode constructed with carbon quantum dot (CQD) sensitized Ti:Fe2O3@GCNN (where GCNNs are graphitic carbon nitride nanosheets) core-shell nanoarrays is demonstrated, showing an excellent photocurrent density as high as 3.38 mA cm-2 at 1.23 V versus a reversible hydrogen electrode (VRHE), 2-fold higher than that of pristine Ti:Fe2O3, which is superior over that of recently reported promising photoanodes. In this ternary system (Ti:Fe2O3@GCNN-CQDs), each component plays a specific role in the process towards superior PEC water oxidation: (i) the vectorial hole transfer of Ti:Fe2O3 → g-C3N4 → CQDs; (ii) the introduction of CQDs leads to high catalytic activity for H2O2 decomposition contributing a high rate activity for water oxidation via a two-step-two-electron water-splitting process; (iii) the favorable electron transport behavior of CQDs. This controlled structure design represents one scalable alternative toward the development of photoanodes for high-efficiency water splitting.

Remedying Defects in Carbon Nitride to Improve both Photooxidation and H2 Generation Efficiencies

The outstanding visible light response of carbon nitride has aroused intense expectations regarding its photocatalysis, but it is impeded by the inevitable defects. Here, we report on a facile melamine-based defect-remedying strategy and resultant carbon

HYDROGEN AND OXYGEN EVOLUTION ON GRAPHITE FIBER-EPOXY MATRIX COMPOSITE ELECTRODES.

The electrochemical behavior of three graphite fiber-epoxy matrix composite materials containing various fiber orientations and fiber loadings was studied. Cyclic voltammetry was used to detect surface functionalities and to determine the electrochemically active surface areas of each material in 1 N H//2SO//4 and 30 weight percent (w/o) KOH. Hydrogen and oxygen evolution were studied on each electrode in 1 N H//2SO//4 and 30 w/o KOH, respectively. Tafel slopes for the hydrogen evolution reaction on the composite electrodes ranged from 0. 14 to 0. 18 V decade** minus **1 while exchange current densities ranged from 4 to 11 multiplied by 10** minus **7 A cm** minus **2. Tafel slopes for the oxygen evolution reaction on the composite materials were high, ranging from 0. 25 to 0. 28 V decade** minus **1.

Photocatalytic Carbon Dioxide Reduction at p-Type Copper(I) Iodide

A p-type semiconductor, CuI, has been synthesized, characterized, and tested as a photocatalyst for CO2 reduction under UV/Vis irradiation in presence of isopropanol as a hole scavenger. Formation of CO, CH4, and/or HCOOH was observed. The photocatalytic activity of CuI was attributed to the very low potential of the conduction band edge (i.e., ?2.28 V vs. NHE). Photocurrents generated by the studied material confirm a high efficiency of the photoinduced interfacial electrontransfer processes. Our studies show that p-type semiconductors may be effective photocatalysts for CO2 reduction, even better than extensively studied n-type titanium dioxide, owing to the low potential of the conduction band edge.

Manganese complexes as models for manganese-containing pseudocatalase enzymes: Synthesis, structural and catalytic activity studies

Manganese complexes of the type [TpMn(X)] and [TpMn(μ-N3)(μ-X)MnTp] (X = acetylacetonate, acac; picolinate, pic and Tp = TpPh,Me for acac, Tp = Tpipr2 for pic complexes) having TpPh,Me (hydrotris(3-phenyl,5-methyl-pyrazol-1-yl)borate)/Tpipr2 (hydrotris(3,5-diisopropyl-pyrazol-1-yl)borate) as a supporting ligand have been synthesized and structurally characterized. IR and X-ray structures suggest that complexes 7 and 9 are binuclear with azido and bidentate ligands (acac/pic) bridging, whereas complexes 6 and 8 are mononuclear with a 5-coordinated metal center. In complex 9 the picolinate is coordinated as tridentate in a η3-fashion, but in complex 7 acac behaves as bidentate, whereas azide is coordinated in a bridging bidentate μ-1,3-manner in both 7 and 9. Since the coordination geometry of the manganese ions in complex 9 is very similar to the active site structure of manganese-containing pseudocatalase, we have tested the catalytic activity of the same towards the disproportionation of hydrogen peroxide. The catalytic results indicated that complex 9 has reasonably good catalase activity and may be suitable, structurally as well as functionally, as a model for the pseudocatalase enzyme.

A readily accessible ruthenium catalyst for the solvolytic dehydrogenation of amine-borane adducts

The use of the readily available complex [Ru(p-Cym)(bipy)Cl]Cl as an efficient and robust precatalyst for homogeneously catalysed solvolysis of amine-borane adducts to liberate the hydrogen content of the borane almost quantitatively is being presented. The reactions can be carried out in tap water, and in aqueous mixtures with non-deoxygenated solvents. The system is also efficient for the dehydrocoupling of dimethylamine-borane under solvent-free conditions. This journal is the Partner Organisations 2014.

Direct Coupling of Thermo- and Photocatalysis for Conversion of CO2–H2O into Fuels

Photocatalytic CO2 reduction into renewable hydrocarbon solar fuels is considered as a promising strategy to simultaneously address global energy and environmental issues. This study focused on the direct coupling of photocatalytic water splitting and thermocatalytic hydrogenation of CO2 in the conversion of CO2–H2O into fuels. Specifically, it was found that direct coupling of thermo- and photocatalysis over Au?Ru/TiO2 leads to activity 15 times higher (T=358 K; ca. 99 % CH4 selectivity) in the conversion of CO2–H2O into fuels than that of photocatalytic water splitting. This is ascribed to the promoting effect of thermocatalytic hydrogenation of CO2 by hydrogen atoms generated in situ by photocatalytic water splitting.

Oxygen-vacancy generation in MgFe2O4 by high temperature calcination and its improved photocatalytic activity for CO2 reduction

MgFe2O4 spinel with abundant oxygen vacancy was synthesized by a simple precipitation method, and tested in photocatalytic reduction of CO2 with water vapor as reductant. A series of characterization including XRD, XPS, EPR, PL spectrum, UV–vis DRS and TPD-CO2 were performed to investigate the influence of calcination temperature on morphology, optical and electronic properties of MgFe2O4 spinel. The results demonstrated that the oxygen vacancy concentration increases first and then decreases with the increase of calcination temperature. By introducing oxygen vacancies, the recombination of photogenerated electron-hole pairs was significantly suppressed, visible light absorption and chemisorption capacity of CO2 were dramatically boosted. Mg-Fe-750 with the richest oxygen vacancies exhibits the highest photocatalytic activity, for which the production rate of CO and H2 was 24.4 and 34.3 μmol/gcat/h, respectively.

Copper phthalocyanine@graphene oxide as a cocatalyst of TiO2 in hydrogen generation

Hydrogen is among the most commonly discussed types of novel energies since it generates high energy in a green manner. Thus, hydrogen production under visible light has been studied with a novel hybrid catalyst including copper(II) phthalocyanine (CuPc) supported on graphene oxide (GO) and TiO2 in a pathway involving formic acid degradation. The homogenous distribution of CuPc on GO has been obtained through synthesis of CuPc in the presence of GO. CuPc@GO carried out the decomposition reaction of formic acid in the presence of TiO2 to afford H2 with TOF of up to 79 h?1 at room temperature. The catalyst indicated 103% and 39% enhancements in H2 generation compared to CuPc/TiO2 and CuPc@GO, respectively.

Ethanol Steam Reforming by Ni Catalysts for H2 Production: Evaluation of Gd Effect in CeO2 Support

Abstract: Ni-based catalysts supported on CeO2 doped with Gd were prepared in this work to investigate the role of gadolinium on ethanol conversion, H2 selectivity, and carbon formation on ethanol steam reforming reaction. For this, catalysts containing 5 wt% of Ni impregnated on supports of ceria modified with different amounts of Gd (1, 5, and 10 wt%) were used. Ex-situ studies of XRPD suggest an increase of the lattice parameters, indicating a solid solution formation between Gd and Ce. Results of TPR showed an increase in metal-support interactions as the content of Gd increased. In situ XRPD studies indicated the formation of a GdNiO ternary phase for the catalysts containing Gd, which is in agreement with the results obtained by XANES. The catalysts were tested at three temperatures: 400?°C, 500?°C, and 600?°C. The conversion and productivity showed dependence with the Gd content and also with the temperature of the reaction. After the catalytic tests, catalysts containing Gd presented filamentous carbon possible due to a change in the reaction pathway. The highest ethanol conversion and H2 productivity were obtained at 600?°C for all catalysts and the best catalyst at this temperature was 5Ni_5GdCeO2. The promising performance of this catalyst may be associate with the lowest formation of GdNiO ternary phase, among the catalysts containing Gd, which means more Ni0 active species available to convert ethanol. Graphical Abstract: [Figure not available: see fulltext.]