Kinetic analysis of surface W species on a series of tungstated-zirconia catalysts has been carried out using time resolved in situ UV-vis spectroscopy. The effects of WO3- and Pt-loading on the reduction-oxidation process between surface W6+ and W(6-delta)+ species, which is correlated to the solid acid properties of tungstated-zirconia, are discussed. The rate of reduction of surface W6+ in 0.5% H-2/He gradually increased with WO3-loading. The rate of re-oxidation process in pure He increased with WO3-loading and showed the maximum value at the theoretical monolayer coverage at around 25 wt.% of WO3; however, that value was decreased by the further addition of WO3. Based on Raman and UV-vis spectroscopy results, the increase in the redox rates was correlated to the growth of polytungstate domain size, and the lower re-oxidation rate at higher WO3-loading was related to the formation of crystalline WO3. The very small amount of Pt(0.02 wt.%)-loading drastically improved both the reduction and re-oxidation rates, and the activation energy significantly decreased from 43 to 9 kJ mol(-1) for the reduction process, and from 62 to 11 kJ mol(-1) for the re-oxidation. Further Pt-loading induced a deleterious effect on the rate and degree of reduction. (C) 2009 Elsevier B.V. All rights reserved.