In the present work the NCO formation from N and CO species is theoretically studied using a computational method based on density functional theory (OFT) and a periodic slab model. For that purpose, the (100) and (111) faces of Pd have been considered, with two different pathways on both surfaces comprising the displacement of CO species. The overall processes are endothermic on Pd(100) and exothermic on Pd(111) and the corresponding energy barriers are larger on Pd(100), compared to Pd(111). Hence, in agreement with the experimental data the NCO formation is more favored on Pd(111). The results are rationalized taking into account charge distributions and electronic structure parameters. (C) 2015 Elsevier B.V. All rights reserved.