The photocatalytic oxidation of acetone vapor on TiO2/ZrO2 thin films is presented in this study. Acetone conversion data collected using a non-circulating tubular reactor are analyzed using a general power law model and a Langmuir-Hinshelwood-Hougen-Watson (LHHW) model; the LHHW model provides a slightly better fit than the 1/2 order power law model. The effects of reaction temperature and relative humidity on the rate of reaction are presented. Using either kinetic model, increasing the reaction temperature from 30 to 77 degrees C (in a dry feed stream) significantly increases the reaction rate constant at a 95% confidence level; however, increasing the temperature from 77 to 113 degrees C does not have a significant effect. The addition of water vapor (50% relative humidity) to the feed stream at 77 degrees C significantly increases the reaction rate constant at a 95% confidence level. Also, at three different temperatures and a single reaction condition, the conversion of acetone is enhanced in the presence of water vapor. No byproducts are detected in the effluent stream of the photocatalytically active reactor.