The general aspects of the synthesis and characterization results of a CuOx/CeO2 catalyst were presented. In addition the principal steps for manufacturing a microchannel reactor and for the coating of the CuOx/CeO2 catalyst onto the microchannels walls, were also summarized. The catalytic activity of this microchannel reactor during the preferential oxidation of CO (CO-PROX) was evaluated employing a feed-stream that simulates a reformate off-gas after the WGS unit. Two activation atmospheres were studied (H2/N2 and O2/N2). The reducing pretreatment improved the resistance to deactivation by formation of carbonaceous species over the catalyst surface at high temperatures. The presence of H2O and CO2 in the feed-stream was also analyzed indicating that the adsorption of CO2 inhibited the conversion of CO at lower temperatures because these compounds modified the active sites through the formation of carbonaceous species on the catalyst surface. Finally, the experimental results of the microreactor performance were compared with CFD simulations that were carried out using a kinetic for the CuOx/CeO2 powder catalyst. The experimental results were reasonably well described by the model, thus confirming its validity.Graphical abstractA CuOx/CeO2 coated microreactor was successfully tested on the CO-PROX reaction under a simulated reformate off-gas feed. The experimental results of the catalytic behavior allowed validating a CFD model based on a kinetic study which have been previously proposed for this microreactor.View high quality image (169K)Highlights► The catalytic behavior of a microreactor during the CO-PROX reaction was evaluated. ► Reducing pretreatment improved the resistance to deactivation. ► The CO2 in the feed-stream inhibited the conversion of CO at lower temperatures. ► The catalytic performance was reasonably well described by the CFD model.