THERMAL-DECOMPOSITION OF TRIMETHYLAMINE ON PT(111) - SPECTROSCOPIC IDENTIFICATION OF SURFACE INTERMEDIATES

The adsorption and decomposition of trimethylamine on a Pt(111) surfac e have been investigated, using high resolution electron energy loss s pectroscopy, Fourier transform infrared reflection-absorption spectros copy and temperature-programmed desorption. Trimethylamine adsorbs mol ecularly at 85 K through the nitrogen lone pair on the Pt(111) surface . Upon heating, four steps of decomposition are observed, starting wit h sequential CN bond cleavage. Three different intermediate surface sp ecies can be identified by vibrational spectroscopy. Heating to 280 K generates a dimethylamino species, (CH3)(2)N. Further heating to 400 K causes the formation of a methylnitrene species, CH3N. This species d ehydrogenates to a methylene amido species, CH2N around 450 K. Finally , complete dehydrogenation takes place at temperatures above 500 K. (C ) 1997 Elsevier Science B.V.