Chemisorption strength

These relative chemisorption strengths enable us to make some simple predictions regarding suitable metal catalysts for specific reactions. For example, a catalyst for the Haber process must chemisorb both N2 and H2, but not too strongly. Since N2 is the less readily bound, we choose Fe, Ru, or Os. The latter two are expensive, so our best choice is iron—usually finely divided, on a suitable refractory support. 

Thus, different chemisorption strengths of the reactants on the catalyst s surface are most likely the origin of the observed isokinetic relationship. In the previous paper19, it was shown... 

Chemisorption of reactants on the Pt surface involves the donation and sharing of electrons between the Pt particles and the reactants. Therefore, changes in the chemisorption must be caused by changes in the electronic properties of either the Pt particles or the reactants. Since the reactants are always the same molecules, the changes in the chemisorption strengths must be caused by changes in the electronic properties of the supported Pt particles. This was illustrated above for the case of the bonding of the n-r intermediate. 

When olefins chemisorb on metal surfaces (in the absence of hydrogen), substantial disruption of the molecules usually occurs measurements of heats of adsorption or of infrared spectra of adsorbed species are therefore of limited utility in establishing behavioral patterns, and more reliance should perhaps be placed on indirect assessments of chemisorption strengths arising from kinetic analysis of reacting systems. This information is of two kinds (a) the sequence of chemisorption strengths of an olefin on a series of metals, and (b) the sequence of chemisorption strengths of different unsaturated hydrocarbons on one metal. 

This is a result often found in chemisorption. The chemisorption strength to a dense surface (surface atoms have high co-ordination, the coordination number... 

While the electrostatic dipole-to-image-dipole interaction is dominant on Cu(lll), its relative importance reduces as passing to more open surfaces, because of increasing chemical contribution. The considerably enhanced chemisorption strength on low coordinated sites is correlated with their up-shifted energy of the d-band center causing a stronger hybridization between the metal d states and molecular orbitals. 

Chemisorption strength as a measure of the surface reactivity toward adsorbed species on a given surface adsorption site can be obtained directly from first-principles computations ... 

In chemisorption, the strength of interaction between molecules and a surface is high enough to be considered a bona fide chemical (covalent) bond. It is not unusual for the strength of chemisorption to rival a true chemical bond. Diatomic oxygen, for example, adsorbs on many metals with a chemisorption strength of over 500 kj/mol ... 

These findings can also be related to Pt being the most active metal in electrochemical hydrogen evolution, owing to the ideal chemisorption strength of the adsorbed reaction intermediate corresponding to the Sabatier principle [80]. 

Structural promoters change the chemical composition, produce lattice defects, alter the electronic structure and the chemisorption strength. 

More accurately, one distinguishes, according to the strength of the bond, between chemisorption (strength of a typical intramolecular chemical bond) and physisorption (strength of a typical intermolecular bond). These details are not of relevance for our context. 

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