Decomposition of CH3NH2 on Pt(111)

S. Y. Hwang, E. G. Seebauer, L. D. Schmidt

Research output: Contribution to journalArticlepeer-review


The adsorption and decomposition of CH3NH2 on Pt(111) have been studied using TPD and AES. The major species observed following adsorption at 300 K are C2N2, H2 and HCN with N2 and CH4 being only a few percent of these species. No CH3NH2 desorbs following 300 K adsorption. HCN desorbs as two major peaks at 480 and 520 K while C2N2 desorbs as several peaks between 700 and 1200 K. Hydrogen desorbs as a peak at ≈420 K from H atom recombination and two peaks at 480 and 520 K from HxCN decomposition. Desorption from the saturated surface produces approximately 4 times more C2N2 than HCN. No carbon residues are left on the surface after heating to 1300 K. Adsorption of CH3NH2 at 100 K produces a monolayer CH3NH2 desorption peak at 230 K and a multilayer, at 135 K. More HCN and less C2N2 form with adsorption at 100 K than at 300 K. Annealing the 100 K adlayer increases the C2N2/HCN ratio. These results indicate that HCN is formed only from HxCN products rather than from H+CN bimolecular reaction as confirmed by hydrogen titration experiments At lower coverages C2N2 desorbs with second-order kinetics, suggesting that this product is formed by combination of adsorbed CN species. These results indicate that CH3NH2 dehydrogenates totally by 600 K and that no C-N bonds are broken on this surface. Onece H2 desorbs to leave CN on the surface, the dimer C2N2 is the only gaseous product which can form, and this occurs avove 1000 K.

Original languageEnglish (US)
Pages (from-to)219-234
Number of pages16
JournalSurface Science
Issue number1-2
StatePublished - Sep 2 1987
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry


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