Three removal processes of surface nitrogen, i.e., (i) the decomposition of the intermediate N2O(a), (ii) its desorption without decomposition and (iii) the associative desorption of nitrogen atoms, were separately studied in a steady-state NO + CO reaction on Pd(I 10) through analysis of the angular and velocity distributions of desorbing products N-2 and N2O. At temperatures below approximately 600 K, the processes (i) and (ii) prevailed, whereas Lit higher temperatures, the process (iii) contributed significantly. The branching was also sensitive to the CO/NO pressure ratio. (C) 2004 Elsevier B.V. All rights reserved.