ELECTROCATALYTIC OXIDATION OF FORMIC-ACID ON ULTRAFINE PALLADIUM PARTICLES SUPPORTED ON A GLASSY-CARBON

The effect of particle size of ultrafine palladium particles on the el ectrochemical oxidation of formic acid in a perchloric acid solution h as been investigated by cyclic voltammetry (CV) and differential elect rochemical mass spectroscopy (DEMS). Except in the hydrogen sorption-d esorption region, only carbon dioxide was observed by the DEMS as an o xidation product, and the profile of the i(mass)-E curve was in fair a greement with that of i-E curves. With a decrease in the palladium par ticle size, the specific activity of the palladium particles for the o xidation of formic acid gradually increased until ca. 3 nm in the mean diameter, and then it steeply decreased.