SPECTROSCOPIC IDENTIFICATION OF AN HCNH SPECIES ON PT(111)

The adsorption and decomposition of methylamine on a Pt(111) surface have been investigated, using infrared reflection-absorption spectroscopy (IRAS) and high resolution electron energy loss spectroscopy (EELS). At 85 K, methylamine is found to adsorb molecularly on Pt(111). After heating the methylamine covered surface to temperatures in the range from 350 to 390 K, new infrared bands at 3371, 1565 and 1325 cm-1 are observed, indicating the presence of a new surface species which is formed by the dehydrogenation of adsorbed CH3NH2. These bands which shift to 2544, 1440 and 1296 cm-1 when using CH3ND2, are assigned to the NH (ND) stretching, CN stretching and CH bending modes of an adsorbed HCNH (HCND) species, respectively. The CH stretching band which is not detectable by IRAS is clearly observed at 2965 cm-1 using off-specular EELS.