Oxygen reduction reaction activity of Pd-based bimetallic electrocatalysts in alkaline medium

• Published in: Catalysis today Vol. 355; pp. 685 - 697
• Main Authors: Bampos, Georgios, Sygellou, Labrini, Bebelis, Symeon
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.09.2020
• Subjects: Alkaline environment; Bimetallic electrocatalysts; Oxygen reduction reaction (ORR); Rotating disk electrode (RDE); Alkaline environment; Pd; Rotating disk electrode (RDE); Oxygen reduction reaction (ORR); Bimetallic electrocatalysts
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2019.06.010

[Display omitted] •ORR activity of Pd–M/C (M: Ag, Ca, Cu, Co, Fe, Ni, Sn, Zn) in 0.1 M KOH was studied.•7.5 wt.% Pd – 2.5 wt.% Cu/C exhibited the highest ORR activity.•Pd–Cu/C, Pd–Zn/C, Pd–Sn/C and Pd–Ni/C exhibited higher specific activity than Pt/C.•7.5 wt.% Pd- 2.5 wt.% M/C exhibited higher ORR activity than 10 wt.% Pd/C.•Pd–Cu/C enhanced ORR activity was mainly associated with optimum Pd lattice strain. A series of 10 wt.% Pd-M (M: Ag, Ca, Co, Cu, Fe, Ni, Sn, Zn) / C electrocatalysts, with Pd to M mass ratio equal to 3:1, were prepared via the wet impregnation method, physicochemically characterized employing various techniques (BET, XRD, TEM, XPS) and electrochemically characterized towards their ORR activity in 0.1 M KOH solution using the RDE technique. Presence of alloy formations was revealed in the bulk of the Pd-Zn and Pd-Sn electrocatalysts. The highest ORR activity was exhibited by the Pd-Cu electrocatalyst, surpassing the activity of the 10 wt.% Pt/C reference. Specific ORR activity higher than that of 10 wt.% Pt/C was also exhibited, in descending order, by the Pd-Zn, Pd-Sn and Pd-Ni electrocatalysts. 10 wt.% Pd/C reference electrocatalyst exhibited the lowest ORR activity among all the tested samples. The superior ORR activity of the Pd-Cu electrocatalyst was mainly associated with an optimum Pd lattice strain.