Ga-Doped Intermetallic Pd3Pb Nanocubes as a Highly Efficient and Durable Oxygen Reduction Reaction Electrocatalyst

Pd-based nanocrystals are a promising candidate as non-Pt electrocatalysts for oxygen reduction reaction (ORR), but their performance still has large room to be improved. Here, we have successfully synthesized Ga-doped Pd3Pb nanocubes with different amounts of Ga by a simple one-pot approach. When evaluated as electrocatalysts for ORR, the Ga-doped Pd3Pb nanocubes exhibited substantially enhanced catalytic properties in an alkaline media relative to the Pd3Pb nanocubes and commercial Pt/C. Interestingly, the Ga-doped Pd3Pb nanocubes showed a volcano-like relationship in ORR activity as a function of the amount of Ga with the 1.76 % Ga-doped Pd3Pb nanocubes (Pd3Pb/Ga-2 NC) being the best ORR electrocatalysts. Specifically, the Pd3Pb/Ga-2 NC/C exhibited the highest specific (7.57 mA cm(-2)) and mass activities (0.91 mA mu g(Pd)(-1)), which were 18.0 and 4.3 times higher than those of the commercial Pt/C. In addition, such Pd3Pb/Ga-2 NC/C displayed the higher durability with an increase of 14.2 % in mass activity after 20000 cycles relative to commercial Pt/C (74.9 % loss). This enhancement in both activity and durability can be attributed to the strong hybridization interactions and the formation of Pd shells on the surface by leaching of Pb.