DFT-GGA calculations have been used to study the chemisorption of CHx (x = 0-3). C2Hy (y = 3-5) and C3Hz (z = 3-8) on Pt(1 1 1) at the coverage of 1/9 ML The adsorption energies, favored binding sites and geometric parameters of adsorption configurations are determined. All the carbonaceous species are found to be adsorbed on Pt(1 1 1) with C atoms sp(3)-hybridized. The geometries of adsorption configurations have been compared with published experimental data to evaluate the reliability of our calculation method. The calculated adsorption energies of C-1 species, ranked in descending order, are as follows, C > CH > CH2 > CH3, and the similar trend has been observed with respect to the chemisorption of C-2 species. As for the C-3 species, propylene prefers binding to the surface in the di-sigma mode and the adsorption energy is calculated to be -0.93 eV. The stepwise dehydrogenation of propane to propynyl (CCCH3) is investigated by calculating the change of reaction heat, which suggests that propylidyne (CCH2CH3) is the most stable species on Pt(1 1 1). Based on the adsorption energies and Bronsted-Evans-Polanyi (BEP) analysis, propyne is predicted to be the most likely starting point for the C-C scission. (C) 2010 Elsevier B.V. All rights reserved.