Promoting ordering degree of intermetallic fuel cell catalysts by low-melting-point metal doping.

Shao, Ru-Yang; Xu, Xiao-Chu; Zhou, Zhen-Hua; Zeng, Wei-Jie; Song, Tian-Wei; Yin, Peng; Li, Ang; Ma, Chang-Song et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

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 L1<sub>0</sub>-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 mg<sub>Pt</sub><sup>-1</sup> at 0.9 V in H<sub>2</sub>-O<sub>2</sub> fuel cells and a rated power density of 1.05 W cm<sup>-2</sup> in H<sub>2</sub>-air fuel cells, with a Pt loading of 0.075 mg<sub>Pt</sub> cm<sup>-2</sup>.