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Chemisorption
About: Chemisorption is a research topic. Over the lifetime, 16298 publications have been published within this topic receiving 554989 citations.
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TL;DR: In this paper, the authors show that at about 25 K the oxygen molecules physisorb on the surface of O 2 Pt and two chemisorbed phases are observed at 90 and 135 K, respectively.
251 citations
TL;DR: Hydrogen is dissociatively adsorbed on the gold particles in Au/Al(2)O(3) catalysts, as demonstrated by a combination of in-situ X-ray absorption spectroscopy, chemisorption, and H/D exchange experiments.
Abstract: Hydrogen is dissociatively adsorbed on the gold particles in Au/Al2O3 catalysts, as demonstrated by a combination of in-situ X-ray absorption spectroscopy, chemisorption, and H/D exchange experimen...
249 citations
TL;DR: In this article, a density-functional theory analysis of surface oxides is presented for low-temperature water-gas shift reaction and methanol oxidation reactions, and the results show that for the conditions typical of technical catalysis the bulk oxide is thermodynamically most stable.
Abstract: As a first step towards gaining microscopic understanding of copper-based catalysts, e.g., for the low-temperature water-gas shift reaction and methanol oxidation reactions, we present density-functional theory calculations investigating the chemisorption of oxygen, and the stability of surface oxides on $\mathrm{Cu}(111)$. We report atomic geometries, binding energies, and electronic properties for a wide range of oxygen coverages, in addition to the properties of bulk copper oxide. Through calculation of the Gibbs free energy, taking into account the temperature and pressure via the oxygen chemical potential, we obtain the $(p,T)$ phase diagram of $\mathrm{O}∕\mathrm{Cu}(111)$. Our results show that for the conditions typical of technical catalysis the bulk oxide is thermodynamically most stable. If, however, formation of this fully oxidized surface is prevented due to a kinetic hindering, a thin surface-oxide structure is found to be energetically preferred compared to chemisorbed oxygen on the surface, even at very low coverage. Similarly to the late $4d$ transition metals (Ru, Rh, Pd, Ag), sub-surface oxygen is found to be energetically unfavorable.
249 citations
TL;DR: In this article, the chemisorption properties of differently prepared model gold/titania interfaces have been compared with the aim of gaining a better understanding of the synergistic interplay between the constituents in gold/Titania catalysts used in low-temperature CO oxidation.
Abstract: The chemisorption properties of differently prepared model gold/titania interfaces have been compared with the aim of gaining a better understanding of the synergistic interplay between the constituents in gold/titania catalysts used in low-temperature CO oxidation. The structurally different gold/titania interfaces were prepared using various techniques, including wet chemical deposition (dip coating) and physical vapor deposition of TiO2 on flat and highly oriented Au(111)/mica films and immobilization of gold colloids on TiO2/Au(111)/mica films as well as on TiO2 powders. The low-temperature activity of small gold colloids anchored on films was corroborated by DRIFTS measurements. CO, CO2, and O2 adsorption/desorption studies were performed on the flat model catalysts with TDS, XPS, and ISS. All flat model systems did not show any significant CO adsorption. Oxygen desorption was evidenced by TDS. The adsorptive properties of powder model catalysts were investigated with DRIFTS, pulse thermal analysis, ...
249 citations
TL;DR: This review is primarily concerned with the identification of the structures of chemisorbed complexes formed between hydrocarbons and metal sur faces through the use of various forms of vibrational spectroscopy, and results obtained with these simplified single-crystal systems are of great value.
Abstract: This review is primarily concerned with the identification of the structures of chemisorbed complexes formed between hydrocarbons and metal sur faces through the use of various forms of vibrational spectroscopy (1) . Thc identification of the chemisorbed species and the study of their reactivities by spectroscopic methods provides an essential basis for the understanding of many classes of metal-catalyzed reactions of hydrocarbons such as hydrogenation/dehydrogenation, hydrogenolysis, isomerization, and metathesis. The particular emphasis of this article is on the study of species formed on metal single crystals that are cut so that specific surfaces of known atomic arrangements, e.g. the [1 1 1], [100], and [1 10] surfaces of face centered cubic (fcc) metals, are exposed to the hydrocarbon adsorbate. Such experiments have become feasible during the past 15 years or so. The principal vibrational spectroscopic techniques used for this purpose are high resolution electron energy loss spectroscopy (EELS) (2) and reflec tion/absorption infrared spectroscopy (RAIRS) (3). In recent years i t has been shown that results obtained with these simplified single-crystal systems are of great value III interpreting
249 citations