Photoelectron spectroscopy studies of the hydrogenation of cyanogen on Pt(111): Comparison with HCN and ethylenediamine

X-ray photoelectron spectra as a function of anneal temperature are used to compare the thermally initiated chemistry of C2N2 + H2 on Pt(111) with that of C2N2, HCN and ethylenediamine. These spectra show that the product of the reaction of C2N2 with coadsorbed hydrogen (the γ state of C2N2 + H2/Pt(111)) is not HCN but is more likely to be a surface di-imine species. The N1s binding energy of this partially hydrogenated species is ∼ 399.3 eV. HCN adsorption on Pt(111) leads to two distinct chemical species with N1s binding energies of 398.6 and 396.9 eV which are interpreted in terms of molecular and dissociative adsorption respectively.