Electrochemical characteristics of PdCoPt/C catalysts synthesized under different conditions

Kinetics of oxygen reduction is studied on PdCoPt/C catalysts with different platinum contents in the metal phase. Catalytic systems are synthesized by the high-temperature method. According to XRD analysis, as the contents of metallic Pd and Co in the catalysts increase, the degree of formation of the alloy between them also increase, which however is accompanied by a considerable growth of metal phase particles. To minimize this adverse effect, a method of sequential metal deposition is put forward. This approach makes it possible to considerably decrease the catalyst grain size as compared the single-step deposition for high metal phase contents in the catalytic system. The kinetics of oxygen reduction on the PdCoPt/C catalysts is studied on the rotating disk electrode. Under model conditions (0.5 M H₂SO₄, 60°C, O₂), the 20Pd13Co5Pt/C catalyst exhibited the highest activity per mass unit (0.5 M H₂SO₄, 60°C, O₂), namely, 9 A/g_{Pd + Pt} at 0.9 V.