Chemisorption


Also found in: Dictionary, Thesaurus, Wikipedia.

chemisorption

[′kem·i‚sȯrp·shən]
(physical chemistry)
A chemical adsorption process in which weak chemical bonds are formed between gas or liquid molecules and a solid surface.

Chemisorption

 

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.

REFERENCES

See references under ADSORPTION.

M. U. KISLIUK

References in periodicals archive ?
Then, silver nanoparticles undergo chemisorption so that the silver nanoparticles fuse to each other and form wiring.
This behavior could be associated to the particle size as it was obtained by chemisorption measurement.
MB adsorption on MC/CABs followed the pseudo-second-order kinetic model, and the ratio-limiting step was chemisorption.
Here the authors report a printing technique to manufacture ultrafine conductive patterns utilizing the exclusive chemisorption phenomenon of weakly encapsulated silver nanoparticles on a photo-activated surface.
the silver nanoparticles are selectively adsorbed through chemisorption on a certain surface-modificated substrate surface, and that the particles exhibit a particle-particle fusion reaction.
Relative values of regression coefficient indicated that the adsorption process was strongly chemisorption process, might be due to the strong attraction between the adsorbent and the adsorbate.
This model is based on the assumption that the sorption follows second order chemisorptions and the integrated equation is usually given as:
Langmuir assumption revealed simultaneous occurrence of both physisorption and chemisorption on the adsorbent surface (Shoaib et al.
The result of the kinetic study shows that the adsorption of Nickel (II) could be described by the pseudo-second-order equation suggesting that the adsorption process is presumably chemisorption.