This paper concerns the physicochemical properties and activity in NO decomposition of a rutile-supported V-O-Mo catalyst, obtained by sol-gel method. Rutile, o-MoO3 and beta-MoO3 are the main phases found by XRD and TEM. Monolayer vanadia-like species containing some Mo atoms substituted for V ones are present on molybdena crystallites. These species show some activity in NO decomposition to N-2 and O-2. An increase in this activity with the increase of O-2 content in the feed indicates surface reconstruction occurring due to interaction with oxygen. (c) 2006 Elsevier B.V. All rights reserved.