Well-dispersed Pd₃Pt₁ alloy nanoparticles in large pore sized mesocellular carbon foam for improved methanol-tolerant oxygen reduction reaction

Oxygen reduction reaction (ORR) catalysts, Pd₃Pt₁ nanoparticles with methanol tolerance, are supported on various carbon supports: mesocellular carbon foam (MSU-F-C), CMK-3, and Vulcan XC-72. The particle size of Pd₃Pt₁ (∼5 nm) is larger than the pore size of CMK-3 (∼3 nm), resulting in the agglomeration of Pd₃Pt ₁ nanoparticles on the external surface of the CMK-3. The large surface area and large pore size of MSU-F-C allows a high degree of dispersion of Pd₃Pt₁ nanoparticles inside the pores. Due to its highly dispersed state, the Pd₃Pt₁/MSU-F-C shows higher ORR activity than Pd₃Pt₁/Vulcan XC-72 and Pd ₃Pt₁/CMK-3. The charge transfer resistance (R _ct), as measured by electrochemical impedance spectroscopy, increases in the order of Pd₃Pt₁/CMK-3 > Pd₃Pt ₁/Vulcan XC-72 > Pd₃Pt₁/MSU-F-C. Pd ₃Pt₁/MSU-F-C is methanol tolerant at 400 rpm in the presence of 0.5 M CH₃OH, while methanol oxidation peaks are observed in the case of Pd₃Pt₁/Vulcan XC-72 and Pd ₃Pt₁/CMK-3.