Pt-Ru polymeric electrocatalysts used for the determination of carbon monoxide

► Pt and Ru contents depend on the Ru(III) concentration in the precursor solution. ► A relationship R = [Pt(IV)]/[Ru(III)] was established for the precursor solution. ► A better dispersion of smaller particles is achieved from a R = 0.5 solution. ► CO oxidation is improved for PtRu catalysts prepared with R = 0.5 solution. ► The relationship between the oxidation current and the CO concentration is linear.