The effect of preparation method on the particle size of palladium and platinum nanoparticles supported on poly( 2,6-dimethy1-1,4-phenylene) oxide electrospun membranes by the wet impregnation technique was investigated. Catalysts with similar metal loading (0.63-0.78 wt.%) possessing various mean metal particle size (2.5-8.7 nm) were prepared employing different impregnation times and nominal metal loadings. The catalysts were tested in the total oxidation of methanol (1000 ppm in air). The catalytic activity of platinum catalysts increased with increasing size of Pt nanoparticles while the effect of the platinum loading was not observed. On the other hand, the catalytic activity of palladium catalysts increased with the increasing palladium loading and did not correlate with the nanoparticle size. (C) 2014 Elsevier B.V. All rights reserved.