Binding of radical species to surfaces: Cluster models for OH on Cu(111)

Abstract

The chemisorptive interaction of the hydroxy radical (OH) with the Cu(111) surface and its consequences for the surface electronic structure are studied by CunOH (n ranging from 1 to 25) cluster models using ab initio Hartree–Fock and correlated wave functions. A comparison of the adsorbate binding at the Cu(111) on top, bridge, and the two threefold hollow [face-centered-cubic and hexagonal-close-packed (fcc and hcp)] sites based on extended geometry optimizations yields the fcc site energetically favored with a binding energy EB=3.1 eV at the configuration interaction (CI) level. Correlation contributions account for about 0.9 eV of the binding and are almost independent of the binding site and cluster size. The OH–metal interaction is characterized by considerable Cu to OH charge transfer filling the partially occupied O 2p lone pair orbitals (OH 1π), while OH to Cu charge transfer involving the OH 3σ orbital is small. As a result, the adsorbate is negatively charged in the presence of the surface and ionic binding contributions become important. This makes the OH–metal binding very similar to that of other radicals such as, e.g., OCH3. The adsorbate binding character is also reflected in the results of cluster core and valence hole states corresponding to OH adsorbate ionization. These results may be compared with experimental photoionization data as they become available.

Adsorption and disproportionation reaction of OH on Ag surfaces: dipped adcluster model study

“…The work functions of Ag(100), Ag(110), and Ag(111) surfaces are 4.61 eV, 4.52 eV, and 4.74 eV [47] respectively. The adsorption behavior of OH on Ag(111) is similar to that on Cu(111) [32] and Ni(111) [29]. All these theoretical studies [29,32] clarified the high-coordinated threefold site as the most stable adsorption site.…”

“…OH binds strongly to a clean metal surface and is at 80 K does not result in azimuthal ordering of adsorbed H 2 O on any of the Ag facets, in markpreferentially adsorbed at high-coordination sites in Ni(100) [29], Ni(111) [29][30][31] and Cu(111) ed contrast to the local ordering observed for H 2 O+O on Ni(111) [5]. Adsorbed H 2 O reacts [32]. The valence orbital structure of hydroxyl is characterized by partially filled 1p orbitals, which with preadsorbed oxygen to form OH species that are bonded with the molecular axis perpendicular are similar in shape and energy to the O 2p states.…”

“…Cu(111) [32] and Ag(111) [33] surfaces. A semiempirical calculation for OH adsorption on Pt and catalytic processes.…”

Effect of Sn on the Reactivity of Cu Surfaces

“…9,[11][12][13] Copper-based catalysts are also used in the automobile industry, 14,15 as well as for acrolein synthesis, dehydrogenation of cycloalkanes, and dehydrogenation of alcohols. 14-16 Accordingly, numerous experimental and theoretical studies have been conducted to understand the fundamental surface chemistry of copper, in terms of the adsorption of species such as hydrogen, 17,18 oxygen, [18][19][20] carbon, 21 hydroxyl, 18,22 CO, and NO. 5,20,23 Here, we present a systematic study of the structures and energetics of monatomic (H, O, N, S, and C) and diatomic (CO, NO, and OH) species on Cu(111).…”

Adsorption of chlorophenol on the Cu(111) surface: A first-principles density functional theory study

“…Optimized geometry for the structure S4 in which the 2-chlorophenoxy radical is adsorbed above a 3-fold hollow fcc site and the H at a neighbouring fcc site. [36] radicals, respectively. We have also found that the interatomic distances between the surface copper atoms coordinating the oxygen atom increase by 5.0% and 2.6% from the bulk value of 2.571 Å in S4 and S5, respectively.…”