1. Electrolysis of water (Unipolar, Bipolar & PEM Technologies)
2. Methane Cracking
3. Ammonia Cracking
Electrolysis of water
Electrolysis of water is the process of using electricity to decompose water into oxygen and hydrogen gas by a process called electrolysis. Hydrogen gas released in this way can be used as hydrogen fuel, or remixed with the oxygen to create oxyhydrogen gas, which is used in welding and other applications.
Sometimes called water splitting, electrolysis requires a minimum potential difference of 1.23 volts, though at that voltage external heat is required from the environment.
Overall reaction: H2O(l) → H2(g) + O(g)
The number of hydrogen molecules produced is thus twice the number of oxygen molecules. Assuming equal temperature and pressure for both gases, the produced hydrogen gas has, therefore, twice the volume of the produced oxygen gas. The number of electrons pushed through the water is twice the number of generated hydrogen molecules and four times the number of generated oxygen molecules.
Diagram showing the overall chemical equation.
Alkaline Water (Unipolar & Bipolar)
A water ionizer (also known as an alkaline ionizer) is a home appliance that claims to raise the pH of drinking water by using electrolysis to separate the incoming water stream into acidic and alkaline components. The alkaline stream of the treated water is called “alkaline water”. Proponents claim that consumption of alkaline water results in a variety of health benefits, making it similar “to the alternative health practice of alkaline diets. Such claims violate basic principles of chemistry and physiology. There is no medical evidence for any health benefits of alkaline water.
Polymer Electrolyte Membrane (PEM)
A proton-exchange membrane, or polymer-electrolyte membrane (PEM), is a semipermeable membrane generally made from ionomers and designed to conduct protons while acting as an electronic insulator and reactant barrier, e.g. to oxygen and hydrogen gas. This is their essential function when incorporated into a membrane electrode assembly (MEA) of a proton-exchange membrane fuel cell or of a proton-exchange membrane electrolyser: separation of reactants and transport of protons while blocking a direct electronic pathway through the membrane.
PEMs can be made from either pure polymer membranes or from composite membranes, where other materials are embedded in a polymer matrix. One of the most common and commercially available PEM materials is the fluoropolymer (PFSA) Nafion, a DuPont product. While Nafion is an ionomer with a per fluorinated backbone like Teflon, there are many other structural motifs used to make ionomers for proton-exchange membranes. Many use polyaromatic polymers, while others use partially fluorinated polymers.
Proton-exchange membranes are primarily characterized by proton conductivity (σ), methanol permeability (P), and thermal stability.
PEM fuel cells use a solid polymer membrane (a thin plastic film) which is permeable to protons when it is saturated with water, but it does not conduct electrons.