Photocatalytic hydrogen production from water

NUS chemists have developed carbon-conjugated covalent organic frameworks for visible light-driven catalytic production of hydrogen gas from water.

Electrolysis breakthrough could solve the hydrogen conundrum

Hydrogen gas is the perfect green fuel—it can be extracted from water and is non-polluting. But although hydrogen is the most abundant element in the universe, it doesn't naturally occur in large quantities as a gas on ...

Neutrons shed light on industrial catalyst for hydrogen production

Collaborators at the Department of Energy's Oak Ridge National Laboratory and U.S. universities used neutron scattering and other advanced characterization techniques to study how a prominent catalyst enables the "water-gas ...

French scientists claim to have created metallic hydrogen

Scientists have long speculated that at the heart of a gas giant, the laws of material physics exhibit remarkable characteristics. In these kinds of extreme pressure environments, hydrogen gas is compressed to the point that ...

Hydrogen-natural gas hydrates harvested by natural gas

A hydrogen-natural gas blend (HNGB) can be a game changer only if it can be stored safely and used as a sustainable clean energy resource. A recent study has suggested a new strategy for stably storing hydrogen, using natural ...

New clues about how ancient galaxies lit up the universe

NASA's Spitzer Space Telescope has revealed that some of the universe's earliest galaxies were brighter than expected. The excess light is a byproduct of the galaxies releasing incredibly high amounts of ionizing radiation. ...

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Hydrogen

Hydrogen (pronounced /ˈhaɪdrədʒən/) is the chemical element with atomic number 1. It is represented by the symbol H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly flammable diatomic gas with the molecular formula H2. With an atomic weight of 1.00794 u, hydrogen is the lightest element.

Hydrogen is the most abundant chemical element, constituting roughly 75% of the universe's elemental mass. Stars in the main sequence are mainly composed of hydrogen in its plasma state. Elemental hydrogen is relatively rare on Earth. Industrial production is from hydrocarbons such as methane with most being used "captively" at the production site. The two largest uses are in fossil fuel processing (e.g., hydrocracking) and ammonia production mostly for the fertilizer market. Hydrogen may be produced from water by electrolysis at substantially greater cost than production from natural gas.

The most common isotope of hydrogen is protium (name rarely used, symbol H) with a single proton and no neutrons. In ionic compounds it can take a negative charge (an anion known as a hydride and written as H−), or as a positively-charged species H+. The latter cation is written as though composed of a bare proton, but in reality, hydrogen cations in ionic compounds always occur as more complex species. Hydrogen forms compounds with most elements and is present in water and most organic compounds. It plays a particularly important role in acid-base chemistry with many reactions exchanging protons between soluble molecules. As the only neutral atom with an analytic solution to the Schrödinger equation, the study of the energetics and bonding of the hydrogen atom played a key role in the development of quantum mechanics.

Hydrogen is important in metallurgy as it can embrittle many metals, complicating the design of pipelines and storage tanks. Hydrogen is highly soluble in many rare earth and transition metals and is soluble in both nanocrystalline and amorphous metals. Hydrogen solubility in metals is influenced by local distortions or impurities in the crystal lattice.

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