Water-gas shift reaction has found new purpose and challenges due to its application in clean power generation systems based on fuel cells. It has been shown that the catalysts performance is dependent on both the metal phase and the nature of the support. In this contribution the modification of Pt/CeO2 catalyst with vanadium was exploited. Spectroscopic techniques revealed that distinct dispersed VOx species were generated onto the catalysts by using different vanadium loadings. The reduction of the catalysts and CO adsorption were monitored by infrared spectroscopy. It was found that the formation/decomposition of surface carbonates is affected by vanadium. Generation of multicoordinated carbonates is inhibited due to the decrease of the exposed cerium surface cations. The catalytic activity increased up to a vanadium surface density of 6 V atoms/nm(2). Improvement in water-gas shift reaction kinetics is associated with the V-O-Ce bonds. (C) 2008 Elsevier Inc. All rights reserved.