In this work, the successful application of spatially resolved measurements in an optically accessible catalytic plate reactor was demonstrated, which allows the detailed investigation of the reaction kinetics of the exothermic CO methanation reaction with high initial CO partial pressure. By means of a movable sampling capillary, the axial gas species concentration profiles over the catalyst plate were measured, and the catalyst surface temperature was determined simultaneously along the reactor through a quartz glass window by means of infrared thermography. A one-dimensional model of the catalytic plate reactor and a Bayesian approach were applied to estimate the kinetic model parameters of the proposed Langmuir-Hinshelwood rate expressions by comparing simulated and measured gas concentration profiles. The validity of using a computationally efficient one-dimensional model was proven by solving a two-dimensional model using the kinetic parameters determined with the one-dimensional model and by comparing the two results. (C) 2010 Elsevier Inc. All rights reserved.