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(physical chemistry)
A chemical adsorption process in which weak chemical bonds are formed between gas or liquid molecules and a solid surface.



the adsorption of substances from the surrounding medium by a liquid or solid, accompanied by the formation of chemical compounds. In a narrower sense, chemisorption is regarded as the chemical binding of a substance by the surface of a solid, or chemical adsorption.

Considerable heat is released in chemisorption: the heat of chemisorption is usually 84–126 kilojoules per mole (kJ/mole), or 20–30 kcal/mole; in some cases—for example, the chemisorption of oxygen on metals—it may exceed 420 kJ/mole (100 kcal/mole). Like chemical reactions, chemisorption usually requires considerable activation energy. Thus, chemisorption is accelerated when the temperature is increased (activated adsorption). Chemisorption is selective—that is, it depends on the chemical affinity of the adsorbed substance for the solid surface.

Physical methods, such as spectroscopy, electron paramagnetic resonance, nuclear magnetic resonance, electron and ion field-emission microscopy, and slow-electron diffraction, are used to study chemisorption. The process plays an important role in heterogeneous catalysis, gas purification, and vacuum technology.


See references under ADSORPTION.


References in periodicals archive ?
Basing on the results gained from the research on adsorption and chemisorption [12], and from the industrial tests focused on the dry sorbent-injection (SI) methods [13, 14], the following conclusions were reached:
The reactions of metal complexes with oxide surfaces result in an irreversible chemisorption called grafting; the product is a hybrid material which retains a memory of its molecular structure but acquires new features of a solid-state material.
o] point towards physisorption as the major and chemisorption as the minor contributor for the adsorption of the inhibitors on the metal surface.
Characteristics determined include particle size, surface area, pore volume, pore size and pore size distribution, absolute density, envelope density, bulk density, chemisorption, and TPD/TPR.
4] retention falls between the chemisorption of phosphate and the electrostatic adsorption of Cl and N[O.
Products featured are used for particle size characterization; surface area, pore size and pore volume by gas adsorption; pore size and volume by mercury porosimetry, active surface area by chemisorption density, zeta potential.
Rubber attached to the filler surface due to chemisorption is called bound rubber.
Common surface atomic contaminants such as H, O, N and C present in various forms of hydrides, oxides, nitrides, and graphites or carbides, respectively, have all been found to have major effects on chemisorption and surface reactions.
This will be achieved by modifying adjacent metal (nano)electrodes with different self-assembled monolayers (SAMs) through a process of chemisorption and selective electrochemical desorption, and will include in this some SAMs that have properties sensitive to light or that can be switched electrochemically to confer additional functionality to the surface and ultimately to the device.
The HealthPro Plus' award-winning design employs progressive phase purification through a pre-filter for micro-particles such as pollen and pet dander, granular activated carbon absorption and pelletized chemisorption cell to remove odors and eliminate harmful chemicals, and the company's patented HyperHEPA filtration technology to eliminate the most dangerous ultra-fine particles.
6% of the total chlorine in PVC can be trapped through chemisorption by alkaline oil shale ash as inorganic compound Ca[Cl.