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In thermolysis, water molecules split into hydrogen and oxygen. For example, at 2,200 °C (2,470 K; 3,990 °F) about three percent of all H 2 O are dissociated into various combinations of hydrogen and oxygen atoms, mostly H, H 2, O, O 2, and OH. Other reaction products like H 2 O 2 or HO 2 remain minor. At the very high temperature of 3,000 ...
Together with hydrogen (H 2), oxygen is evolved by the electrolysis of water. The point of water electrolysis is to store energy in the form of hydrogen gas, a clean-burning fuel. The "oxygen evolution reaction (OER) is the major bottleneck [to water electrolysis] due to the sluggish kinetics of this four-electron transfer reaction."
Since hydrogen can be used as an alternative clean burning fuel, there has been a need to split water efficiently. However, there are known materials that can mediate the reduction step efficiently therefore much of the current research is aimed at the oxidation half reaction also known as the Oxygen Evolution Reaction (OER).
2 O) is a simple triatomic bent molecule with C 2v molecular symmetry and bond angle of 104.5° between the central oxygen atom and the hydrogen atoms. Despite being one of the simplest triatomic molecules , its chemical bonding scheme is nonetheless complex as many of its bonding properties such as bond angle , ionization energy , and ...
The two hydrogen 1s orbitals are premixed to form a 1 (σ) and b 2 (σ*) MO. Mixing takes place between same-symmetry orbitals of comparable energy resulting a new set of MO's for water: 2a 1 MO from mixing of the oxygen 2s AO and the hydrogen σ MO. 1b 2 MO from mixing of the oxygen 2p y AO and the hydrogen σ* MO. 3a 1 MO from mixing of the a ...
Oxygen gas can also be produced through electrolysis of water into molecular oxygen and hydrogen. DC electricity must be used: if AC is used, the gases in each limb consist of hydrogen and oxygen in the explosive ratio 2:1. A similar method is the electrocatalytic O 2 evolution from oxides and oxoacids.
Free oxygen is produced in the biosphere through photolysis (light-driven oxidation and splitting) of water during photosynthesis in cyanobacteria, green algae, and plants. During oxidative phosphorylation in cellular respiration, oxygen is reduced to water, thus closing the biological water-oxygen redox cycle.
Photons trapped by photosystem II move the system from state S 0 to S 1 to S 2 to S 3 and finally to S 4. S 4 reacts with water producing free oxygen: 2 H 2 O → O 2 + 4 H + + 4 e −. This conversion resets the catalyst to the S 0 state. The active site of the OEC consists of a cluster of manganese and calcium with the formula Mn 4 Ca 1 O x ...