Carbon supported intermetallic compound nanoparticles with high activity and stability are promising cathodic catalysts for oxygen reduction reaction in proton-exchange-membrane fuel cells. However, the synthesis of intermetallic catalysts suffers from large diffusion barrier for atom ordering, resulting in low ordering degree and limited performance. We demonstrate a low-melting-point metal doping strategy for the synthesis of highly ordered L10-type M-doped PtCo (M = Ga, Pb, Sb, Cu) intermetallic catalysts. We find that the ordering degree of the M-doped PtCo catalysts increases with the decrease of melting point of M. Theoretic studies reveal that the low-melting-point metal doping can decrease the energy barrier for atom diffusion. The prepared highly ordered Ga-doped PtCo catalyst exhibits a large mass activity of 1.07 A mgPt−1 at 0.9 V in H2-O2 fuel cells and a rated power density of 1.05 W cm−2 in H2-air fuel cells, with a Pt loading of 0.075 mgPt cm−2.
The development of highly ordered intermetallic catalyst for oxygen reduction reactions suffers from large diffusion barrier for atom ordering. Here, the authors use a low melting-point metal doping strategy to synthesize a series of highly ordered metal-doped platinum–cobalt alloy fuel cell catalysts.