The activity and selectivity for the preferential oxidation of CO (PROX), on Pt- and Pd-supported catalysts, have been studied using a high-throughput method of screening and analysis of catalysts. Two families of catalysts were selected on the basis of existing literature results: one family consisted of platinum and palladium supported on alumina and titania promoted with ceria, and the other family of the same metals interdispersed in various oxides. The activity of these materials was first screened using in situ infrared thermography (IRT). The samples with the higher activity were selected for study in a parallel reactor with 10 microreactors and in a single recycle reactor. Platinum supported on titania promoted with ceria showed the highest activity and selectivity, in particular, the 1% Pt - 15% CeO2/TiO2 catalyst appears to be a suitable candidate for the PROX reaction at temperatures below 90 degreesC.