The sulfur induced reconstruction of the Pt(S)-[6(111)×(100)] surface

Lanzillotto, Ann-Marie; Bernasek, Steven L.

doi:10.1063/1.450241

Cited by 20 publications

(12 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this paper we report STM results obtained during the characterization of stepped Pt(111) surfaces dosed with CO after being precovered with a p(2×2) sulfur overlayer. The initial sulfur dosing was found to induce a slow step doubling on the surface, also already observed by LEED …”

Section: Introductionsupporting

confidence: 71%

“…Also, a displacement by 1 / 3 in the diagonal direction of the original unit cell can be seen in the patterns of the two terraces for the single and double (but not triple) steps, indicating that the steps are oriented in the plane of one of the other (111) directions. As mentioned in the Introduction, the doubling of the steps upon sulfur adsorption has been previously observed by LEED . The sulfur p(2×2) overlayer is quite resistant to poisoning and can be maintained under vacuum for several days.…”

Section: Resultsmentioning

confidence: 61%

See 1 more Smart Citation

Coadsorption of Sulfur and Carbon Monoxide on Platinum Single-Crystal Surfaces Studied by Scanning Tunneling Microscopy

Zaera

Salmerón

1998

Langmuir

View full text Add to dashboard Cite

The spatial distribution of sulfur and carbon monoxide coadsorbed on stepped Pt(111) surfaces was characterized by low-energy electron diffraction and scanning tunneling microscopy. The formation of a p(2×2) sulfur overlayer on the platinum substrate leads to the slow doubling of the original monatomic steps, but subsequent room temperature exposure of that surface to CO removes the reconstruction and induces the formation of approximately 50 Å wide intermediate steps covered with carbon monoxide exclusively. Additional CO dosing causes the development of more complex structures at the edge of the steps, where the excess sulfur is pushed to the bottom of the step while the rest of the terrace becomes covered with CO + S intermixed layers. The implications of these results for catalysis are briefly discussed.

show abstract

Section: Introductionsupporting

confidence: 71%

Section: Resultsmentioning

confidence: 61%

Coadsorption of Sulfur and Carbon Monoxide on Platinum Single-Crystal Surfaces Studied by Scanning Tunneling Microscopy

Zaera

Salmerón

1998

Langmuir

View full text Add to dashboard Cite

show abstract

“…In these highly stepped regions, S alone causes step restructuring by doubling step heights and terrace widths. 22 The subsequent exposure to CO displaces S from the bottom of the step edges, as in the flatter regions of the surface and, in addition, it splits the double steps into two monoatomic steps. 23 The new terraces are occupied alternately by either S or CO.…”

Section: Co-adsorption and Site Competitionmentioning

confidence: 99%

Chemisorption, diffusion and reactions on surfaces by scanning tunnelling microscopy

Salmerón¹,

Dunphy²

1996

Faraday Disc.

View full text Add to dashboard Cite

We discuss several applications of scanning tunneling microscopy (STM) to studies of chemisorption and surface reactivity. These include : (i) adsorbateadsorbate interactions and diffusion phenomena. We illustrate this with the example of S on Re(0001), where the hopping (diffusion) of S atoms across surface sites was viewed by use of STM. The observed atomic motion was found to be highly correlated, as in a lattice 'liquid'; (ii) interaction between different co-adsorbed species, including S and CO, and benzene and CO, that display both repulsive and attractive interactions leading to the segregation or intermixing of the adsorbates; and (iii) adsorbate-substrate interactions that lead to various surface reconstructions, step restructuring and faceting. We give recent results showing CO and S inducing step restructuring and reconstruction of a Pt(ll1) crystal substrate. Finally, we illustrate the unique capability of STM of operating in virtually any environment by studying the structure of Pt( 110) and Pt( 11 1) surfaces in various gas environments (H, , 0, , CO, propylene) and at pressures of up to 1.6 atm.

show abstract

“…As indicated in ref. (7), 'the reconstruction time was not reproducible at a particular overall sulphur coverage and annealing temperature in that range. The time variation of 15 s to 15 min in that temperature range is likely to be the time it takes the sulphur atoms to diffuse to the steps, rather than the surface reconstruction time'.…”

Section: Experiments Under Catalytic Conditionsmentioning

confidence: 92%

“…When traces of sulphur were measured by AES (0, 2 0.01-0.05 monolayer) the surface reconstruction occurs in complete agreement with the work of ref. (7). The surface reconstruction is not induced by hydrogen but by sulphur present as an impurity in the bulk or transferred to the surface by hydrogen.…”

Section: Difusion Of Sulphur From the Bulk To The Surface By Annealin...mentioning

confidence: 99%

Modifications of platinum model catalysts by sulphur: effect on reactions of labelled hexanes

Maire¹,

Lindauer²,

Garin³

et al. 1990

J. Chem. Soc., Faraday Trans.

View full text Add to dashboard Cite

The presence of impurities, such as sulphur, oxygen or calcium, can poison or promote the catalytic activity of platinum model catalysts by induced reconstruction of the surface. Such a reconstruction can make available new active sites or eliminate others. We focus our attention on the reconstruction of a platinum stepped surface Pt(S) -[6(111) x (loo)] induced by sulphur, hydrogen plus sulphur and hydrogen plus sulphur plus hydrocarbons and on the consequences on the catalytic activity and selectivity for the skeletal rearrangement of labelled hexanes. Very small sulphur coverages induce, in the presence of hydrogen and hydrocarbons, surface reconstructions dependent on the preferential adsorption of sulphur at the step edge as already described by Lanzillotto and Bernasek for the sulphur-induced reconstruction of the Pt(S) -[6(111) x (loo)] surface. At 350°C and at isoconversion the increase of sulphur coverage results in a decrease of the extensive hydrogenolysis and in an increase in the isomerization via a bond-shift mechanism. The behaviour of a supported Pt/AI,O, catalyst of low dispersion working in an unpurified hydrogen flow is then well simulated. The results provide a good example of the use of surface science techniques to elucidate the role of minor impurities in controlling catalytic reactions.

show abstract

The sulfur induced reconstruction of the Pt(S)-[6(111)×(100)] surface

Cited by 20 publications

References 20 publications

Coadsorption of Sulfur and Carbon Monoxide on Platinum Single-Crystal Surfaces Studied by Scanning Tunneling Microscopy

Coadsorption of Sulfur and Carbon Monoxide on Platinum Single-Crystal Surfaces Studied by Scanning Tunneling Microscopy

Chemisorption, diffusion and reactions on surfaces by scanning tunnelling microscopy

Modifications of platinum model catalysts by sulphur: effect on reactions of labelled hexanes

Contact Info

Product

Resources

About