Cathodic reduction of oxygen on PdCo/C catalyst synthesized based on commercial Pd/C catalyst

The data on the cathodic PdCo/C catalyst prepared by high-temperature synthesis from 20 wt % Pd/C (E-TEK) are shown. According to XRD data, the catalyst represents an alloy with the preferential composition of Pd₂Co. The kinetics and mechanism of oxygen reduction on the PdCo/C catalyst are studied by the methods of rotating disk electrode, rotating ring-disk electrode, and electrochemical impedance. It is shown that oxygen is reduced preferentially to water (k ₁) but in the potential range more negative than 0.6 V, the ratio of constants k ₁/k ₂ decreases, which suggests that the contribution of the reaction that proceeds through the formation of H₂O₂ (k ₂) increases. The activity of PdCo/C catalyst under model conditions in 0.5 M H₂SO₄ was assessed to be 15 mA/mg_cat at a potential of 0.7 V.