The activity of Vulcan supported Pt nanoparticles (Pt40%/Vulcan XC 72) towards oxidation of methanol and ethanol is increased by admixing them with zeolite-type cesium salts of heteropolymolybdic and heteropolytungstic acids Cs(2 5)H(0 5)PMo(12)O(40) Cs(2 5)H(1 5)SiMo(12)O(40) Cs(2 5)H(0 5)PW(12)O(40) and Cs(2 5)H(1 5)SiW(12)O(40) It is apparent from IR measurements that these salts remain the Keggin-type structure They are electroactive and undergo reversible redox transitions as well as they are hydrated and contain mobile protons As evidenced from cyclic voltammetric stair case voltammetric and chronoamperometric diagnostic experiments the electrocatalytic enhancement effect has been most pronounced upon application of phosphododecamolybdate and phosphododecatungstate salts The overall activation effect may also reflect the micro and mesoporous (zeolite type) high surface area morphology of polyoxomet allate cesium salts The presence of well-defined polyoxometallate clusters in the vicinity of Pt is expected increase population of reactive oxo groups at the electrocatalytic interface (C) 2010 Elsevier B V All rights reserved