ИСТИНА

It was found that the specific reaction rate of methanol oxidation reaction (MOR) at CVA peak on Pt0Au per cm2 of electrochemical active surface area (EASA) was substantially lower that for pc Pt. At the same time the smaller was the Pt deposit the lower was the activity of Pt0Au. EASA was measured by the hydrogen adsorption. The reverse situation in comparison with MOR was found for the formic acid oxidation reaction (FAOR). First of all the specific Pt activity for all Pt0Au samples was significantly higher than that for pc Pt. Secondly, the activity decreased with the amount of Pt deposits. Different behavior of Ptх0Au in MOR and FAOR is explained by the fact that the chemisorption of СН3ОН requires a larger area (≥ 3 Pt surface atoms), whereas its single-site adsorption results in the formic acid oxidation by the direct path. It is assumed that the Pt/Au interface of particles plays an important role in the formation of active sites (“ensembles”) for FAOR.