PdPt alloy nanocubes as electrocatalysts for oxygen reduction reaction in acid media

• PdPt alloy nanocubes were synthesised in the presence of polyvinylpyrrolidone (PVP).
• PVP was removed from PdPt surface by centrifugation and CO adsorption and oxidation.
• PdPt nanocubes were used as catalysts for oxygen reduction reaction in 0.5 M H2SO4.
• The alloyed PdPt catalysts showed an enhanced electrocatalytic activity for ORR.
• The electroreduction of oxygen proceeded via 4-electron pathway on PdPt catalysts.

In this work, PdPt alloy nanocubes with different metal ratios were synthesised in the presence of polyvinylpyrrolidone (PVP). The surface morphology of the PdPt samples was characterised by transmission electron microscopy (TEM). TEM images showed that PdPt nanoparticles were cubic-shaped and the average size of the cubes was about 8–10 nm. Their electrocatalytic activity towards the oxygen reduction reaction (ORR) was studied in 0.5 M H2SO4 using the rotating disc electrode method. All the alloyed catalysts showed enhanced electrocatalytic activity for ORR as compared to the monometallic cubic Pd nanoparticles. Half-wave potential values for PdPt catalysts were comparable with that of Pt nanocubes. From the alloyed catalysts Pd36Pt64 exhibited the highest specific activity, which was only slightly lower than that of cubic Pt nanoparticles. The Koutecky–Levich analysis revealed that the reduction of oxygen proceeded via 4-electron pathway on all the electrocatalysts studied.

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