中国科学院上海硅酸盐研究所施剑林团队报道了，氧空位介导的原子间有序超细铂合金纳米颗粒合成提高燃料电池性能。相关研究成果发表在2024年10月22日出版的《美国化学会杂志》。

铂基金属间化合物有望成为质子交换膜燃料电池中，氧还原反应（ORR）的高活性催化剂，但在原子间有序和超细金属间纳米粒子的可控合成方面，仍面临巨大挑战。

该文中，研究人员提出了一种通过机械合金化的氧空位介导的原子扩散策略，以减少从原子间无序到有序过渡的能量势垒，并通过强M-O-C键抵抗颗粒间烧结。这种合成产生了一种纳米级的核/壳结构，其具有原子间有序的PtM核和厚度为两到三个原子层的Pt壳，并且可以扩展到多组分PtM（M=Co、FeCo、FeCoNi、FeCoNiGa）系统。

压缩应变引起的Pt外壳中的电子富集，导致费米能级以下的反键轨道占据增强，OH*解吸动力学加速。优化的PtCo–O/C-6催化剂在燃料电池中具有优异的ORR活性（在0.9 ViR自由下的质量活性=1.28 A mgPt^–1，在H₂–O₂/–空气中的峰值功率密度=2.38/1.25 W cm^–2）和耐久性（在空气条件下50小时内活性损失约1%），总Pt负载量为0.1 mgPt cm^–2。此外，研究建立了一个系统的相关性，以阐明氧空位下高度有序的金属间催化剂的形成机制。

该研究为大规模生产高度有序和纳米级Pt分散的金属间催化剂，提供了一种通用方法。

附：英文原文

Title: Oxygen Vacancy-Mediated Synthesis of Inter-Atomically Ordered Ultrafine Pt-Alloy Nanoparticles for Enhanced Fuel Cell Performance

Author: Fantao Kong, Yifan Huang, Xu Yu, Min Li, Kunming Song, Qiuyun Guo, Xiangzhi Cui, Jianlin Shi

Issue&Volume: October 22, 2024

Abstract: Pt-based intermetallics are expected to be the highly active catalysts for oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells but still face great challenges in controllable synthesis of interatomically ordered and ultrafine intermetallic nanoparticles. Here, we propose an oxygen vacancy-mediated atomic diffusion strategy by mechanical alloying to reduce the energy barrier of the transition from interatomic disordering to ordering, and to resist interparticulate sintering via strong M–O–C bonding. This synthesis results in a nanosized core/shell structure featuring an interatomically ordered PtM core and a Pt shell of two to three atomic layers in thickness and can be extended to the multicomponent PtM (M = Co, FeCo, FeCoNi, FeCoNiGa) systems. The electron enrichment in the Pt outer shell induced by the compressive strain leads to the enhanced antibonding orbital occupation below the Fermi level and accelerated OH* desorption kinetics. The optimized PtCo–O/C-6 catalyst presents excellent ORR activity (mass activity = 1.28 A mgPt–1 at 0.9 ViR-free, peak power densities = 2.38/1.25 W cm–2 in H2–O2/–air) and durability (～1% activity loss in over 50 h in air condition) in fuel cells at a total Pt loading of 0.1 mgPt cm–2. Furthermore, we establish a systematic correlation to elucidate the formation mechanisms of highly ordered intermetallic catalysts underlying oxygen vacancies. This study provides a general approach for the large-scale production of highly ordered and nanosized Pt-dispersed intermetallic catalysts.

DOI: 10.1021/jacs.4c07185

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c07185