E. Janin

Hydrogen adsorption on the Pt(111)(3 × 3)R30°-Sn surface alloy studied by high resolution core level photoelectron spectroscopy

Investigation of the clean and atomic hydrogen covered Pt(111)(root 3 x root 3)R30 degrees-Sn surface alloy has been carried out using high resolution core level photoelectron spectroscopy, The Pt 4(7/2) spectrum recorded from the clean surface alloy shows a single surface peak shifted - 0.25 eV relative to the bulk. Its interpretation by means of a thermodynamical model using Born-Haber cycles confirms the surface alloy model. Adsorption of H does not change the line shape of the Sn 4d core level while a new surface component shifted by 0.59 eV compared to the bulk peak appears in the Pt 4(7/2) spectrum. These results are discussed in the light of the thermodynamical calculations, H atoms are believed to bind only to Pt atoms, and their adsorption site seems to be influenced by the tin present in the surface layer.

Adsorption and bonding of 2-butenal on Sn/Pt surface alloys

The adsorption of 2-butenal on the Pt(111), Pt(111)Sn-(2 x 2), and Pt(111)Sn-(root3 x root3)R30degrees surfaces has been studied by high-resolution photoelectron spectroscopy and DFT calculations. On Pt(111) 2-butenal adsorbs at a threefold hollow in a eta(3)(C,C,O) configuration. A similar geometry is observed for Pt(111)Sn-(2 x 2), although the oxygen coordinates to tin instead of platinum. As the surface coverage of tin increases, as for Pt(111)Sn-(root3 x root3)R30degrees, the most stable adsorption geometry changes to eta(1)(O), where the carbonyl oxygen once again coordinates to tin. The carbonyl bond thus retains an activated character as Pt/Sn alloys are formed. The alkene/surface interaction is, however, dramatically influenced at increasing surface concentrations of tin.

Adsorption of SO2 on Cu(100) and Cu(100)-c(2 × 2)-O surfaces studied with photoelectron spectroscopy

Abstract The adsorption of SO 2 on clean Cu(100) and Cu (100)- c (2 × 2)- O surfaces at room temperature has been studied using high resolution core-level photoelectron spectroscopy. On both surfaces, two types of atomic S and two types of SO 3 are found as shown by their well separated S 2p binding energies. On the Cu (100)- c (2 × 2) O surface, pre-adsorbed oxygen inhibits the SO 2 decomposition and accelerates the SO 2 reaction with the substrate which benefits SO 3 formation.

CeO2 on Si(111) 7×7 and Si(111)–H 1×1, an interface study by high-resolution photoelectron spectroscopy

Abstract The formation of the CeO 2 –Si(111) interface was studied by high-resolution photoelectron spectroscopy. It is shown that CeO 2 and Si(111) forms a highly reactive interface with a strong interdiffusion of Si into the CeO 2 . A passive silicon surface formed by saturating the Si dangling bonds with hydrogen is considerably less reactive. Defects on the surface, however, act as nucleations centres for reactions of a Si:Ce:O matrix. Oxygen leaves the surface at about 800°C and at 1000°C a surface reconstruction of Si(111)–Ce 2×2/√3×√3 is formed.

Pt3Ti alloy formation on the Pt(111) surface

Titanium growth on the Pt(lll) surface has been studied by scanning tunneling microscopy (STM) and photoelectron spectroscopy. Ti grows in islands with a coverage-dependent morphology and dispersio ...

High resolution synchrotron radiation PES study of PbPc deposited on Pt(111)

We studied lead phthalocyanine (PbPc) films sublimated under UHV conditions on a clean Pt(111) substrate. We report results from high resolution photoelectron spectra of the Pb 5d, Ph 4f, C 1s, N 1 ...

CO bonding on tin modified Pt()-(1×2)

The influence of tin on the bonding of CO to Pt(l 10) has been studied using high-resolution electron energy loss spectroscopy, density functional theory and photoelectron spectroscopy. CO binds on-top to platinum at all investigated tin and CO coverages. Bonding of CO in Sn-Pt alloy rows is weakened compared to clean Pt(l 10). However, several different adsorption sites in Pt-only rows, inequivalent with regard to their coordination environment, show very similar characteristics with respect to CO adsorption.

Corrosive adsorption of Sn on the Pt(110)(1 x 2) surface

Room temperature deposition of Sn on the Pt(110)(1 x 2) surface has been studied by scanning tunnelling microscopy and core level photoelectron spectroscopy. At low coverage Sri is found in three d ...

Ge/(111)3x1:K/Sn; On the influence of tin substitution in a metal induced 3x1 reconstruction

Go-adsorption of tin and potassium is found to induce a 3x1 reconstruction on the Ge(lll) surface. A very small amount of tin influences the Ge 3d core level spectra substantially compared to the G ...

Surface structures on sputtered/annealed WC(0001)

We use scanning tunnelling microscopy, Auger electron spectroscopy and low energy electron diffraction to study different tungsten and carbon terminated surface reconstructions on the sputtered/annealed WC(0001) surface. The tungsten terminated surface encompasses a ( 7 × 7)R19° W-trimer structure, a ( 3 × 7) reconstruction representing a transition structure from the ( 7 × 7)R19° reconstruction to a (6 × 1) phase which consists of a quadratic W overlayer on the first close-packed carbidic carbon layer. The carbon terminated WC(0001) surface consists of a single graphitic carbon layer on top of the (6 × 1) structure.