Adsorption energetics

Hammer B, Hansen L B and Norskov J K 1999 Improved adsorption energetics within density functional theory using revised Perdew-Burke-Enerhof functionals Phys. Rev. B 59 7413-21... 

B. Hammer, F. B. Hansen, and J. K. Nprskov, Improved Adsorption Energetic within Density-Functional Theory Using Revised Perdew Burke Emzerhof Functionals, Phys. Rev. B 59 (1999), 7413. 

There has been substantial progress in experimental and theoretical surface analytical methods over the last years. Methods based on X-rays and UV light for diffraction, absorption, or photoelectron spectroscopies benefit from new generation synchrotron light sources. To name a few, surface experimental methods include XPS, AES and SIMS for investigating the surface chemistry A

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From our krypton adsorption data, we must conclude that the adsorption energetics are the same within experimental error on all three mica samples for the range 0.2 <0< 0.8 (with the possible exception of the barium muscovite up to 0 0.4, as noted above). We have calculated differential heats and entropies... 

L-cysteine is oriented roughly perpendicular to the step edge. These orientations agree with those predicted using density functional theory and indicate significantly different orientations of the two enantiomers of cysteine on the chiral Au(17, 11, 9) surfaces and significant differences in their adsorption energetics. 

Ge Q, Kose R, King DA (2000) Adsorption energetics and bonding from femtomole calorimetry and from first principles theory. Adv Cat 43 207... 

Relevant previous publications on adsorption energetics include, besides the classical text by Gregg and Sing [2], a more recent book by Rouquerol et al. [3] on adsorption by powders and porous solids. This book covers thermodynamic aspects of adsorption at the gas—sohd and liquid—solid interfaces, and an entire chapter is devoted to adsorption on activated carbons. In addition, two books by Bansal et al. [4, 5] review in commendable detail the fiterature on adsorption by activated carbons. 

As discussed by Hobza et al. (1981), in studying the adsorption energetics of water on silica surfaces, the appropriate reaction to use is... 

Adsorption studies on zeolite X and Y of varying sodium content (obtained by a variation in the Si/Al ratio and by NH4+ exchange) revealed that there are 2 types of surface cations in the zeolites which exhibit nearly equal adsorption energetics (66). These 2 cations are characterized by site III (which is preferentially removed from the structure) and site II. Adsorption heats for gases such as CH4, Xe, and Kr suggested an effective charge of 0.66 esu for the surface sodium ions. 

Using a mesostmctnred alnminosiUcate of the MCM-41 type with the same composition but varying the pore size from 2.3 to 9.3 mn, Tanchoux et al measnred the adsorption energetics and the catalytic isomerisation of 1-hexene. The authors could demonstrate that the geometry-dependent contributions dominated catalytic behaviour over all other factors. 

The remainder of this chapter will focus on halogen chemisorption on transition metal and semiconductor surfaces, with particular emphasis on adsorption-desorption kinetics, adsorption energetics, and the structure of the chemisorbed layers. Following a description of the general features of halogen adsorption, a review of results for specific surfaces will be presented, grouped by crystallographic structure and orientatiom... 

Two factors play important roles in the study of adsorption equilibria of mixtures on heterogeneous adsorbents like activated carbon and hence have received attention in the development of various models. They are (1) the size difference between the adsorbate molecules and (2) the adsorption energetic heterogeneity, or the structural heterogeneity of the adsorbent if the adsorbate is nonpolar. For many conditions, these two factors are adequate to account for the nonideal behavior of the adsorbed phase, and they are readily accounted for by the MPSD model. This model needs to be further applied and tested in many systems to verify its capability, and it needs to be modified (fine-tuned) to account for many factors such as the irregular structure of the micropore as well as the inclusion of functional groups to deal with polar adsorbates. 

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