The electrochemical activation mode as a way to exceptional ORR performance of nanostructured PtCu/C materials

A new electrochemical approach which gives important knowledge about effect of the activation potentials range on the catalysts activity in ORR. The results obtained show how optimization of the pretreatment conditions of PtCu/C catalysts can significantly increase their operation characteristics due to the reorganization of the surface of nanoparticles. • Easy preparation of PtCu/C alloy nanocatalysts by one-pot wet-synthesis methods. • An active surface of bimetallic nanoparticles formed by electrochemical activation. • The peculiarities of the Cu atoms dissolution affect the activity of de-alloyed PtCu NPs. • PtCu/C catalysts activity in the ORR depends on the Upper potential limit at the activation stage. • Activation of PtCu/C catalysts at the UPL above 1.05 V leads to a significant decrease in their ORR activity. The nanostructured PtCu x /C catalysts with an average nanoparticle size of 3–5 nm, which significantly surpass in activity the commercial Pt/C analog in the oxygen electroreduction reaction (ORR), were obtained by the chemical reduction. A detailed analysis of the activation potentials range effect on the catalysts electrochemical performance in particular, on the microstructure of bimetallic catalysts with small nanoparticles, has been carried out. The upper potential limit, which limited the range of the electrode activation potentials, had a significant effect on the PtCu/C catalysts mass activity and specific activity in the ORR, but does not affect to the electrochemically surface area and materials compositions. Thus, an important phenomenon has been noted in which materials with the same composition differ significantly in their functional characteristics in the ORR, depending on the electrochemical activation conditions. Original approach to electrochemical study is presented, which helps to understand the effect of the activation potentials range on the surface layers reorganization of bimetallic nanoparticles in catalysts.