Role of steps and kinks in catalytic activity

L. P. Ford, Paul Blowers, R. I. Masel

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

In the literature, there is the idea that steps and kinks are the active sites for chemical reactions, but the experimental data are far from convincing. In this article we see if there is a correlation between step atom density, van Hardeveld and Hartog coordination numbers, or the electronic coordination number and reactivity for a number of simple decomposition and hydrogenolysis reactions on platinum as measured by temperature-programmed desorption. We have examined reactions of ethylene nitric oxide, and methanol on (111), (110)-(×1), (110)-(2×1), (100)-hex, (100)-(×1), (210) (511) and (331) platinum surfaces. We have done a statistical analysis of our data to see it any of the correlations are non-negligible. We find that, in general, stepped surfaces have different reactivity than close-packed planes, but some stepped surfaces are more active than Pt(111) while others are less active than Pt(111). There are negligible correlations between step atom density and catalytic activity for our reactions. Similarly, there are negligible correlations between reactivity and the lowest or average van Hardeveld and Hartog coordination numbers. Calculations were done to understand the variations. There are correlations between the lowest electronic coordination number and reactivity for only the reaction of methanol to carbon dioxide, and between the average electronic coordination number and reactivity for the reaction of methanol to methane. The first correlation is not surprising considering the special nature of the rate-limiting step of this reaction. The second correlation raises many yet-unanswered questions. We find that, in general stepped surfaces relax to more stable geometries. The relaxation process raises the electronic coordination number of the surface atoms. After relaxation, there is not a large difference between the coordination of atoms of platinum stepped surfaces and Pt(111).

Original languageEnglish (US)
Pages (from-to)1705-1709
Number of pages5
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume17
Issue number4
StatePublished - Jul 1999
Externally publishedYes

Fingerprint

catalytic activity
Catalyst activity
coordination number
reactivity
Platinum
Methanol
Atoms
platinum
methyl alcohol
electronics
atoms
Hydrogenolysis
Methane
Nitric oxide
hydrogenolysis
Relaxation processes
Temperature programmed desorption
Carbon Dioxide
nitric oxide
Chemical reactions

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Physics and Astronomy (miscellaneous)
  • Surfaces and Interfaces

Cite this

Role of steps and kinks in catalytic activity. / Ford, L. P.; Blowers, Paul; Masel, R. I.

In: Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, Vol. 17, No. 4, 07.1999, p. 1705-1709.

Research output: Contribution to journalArticle

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