Wu Zhi-Peng, Caracciolo Dominic T, Maswadeh Yazan, Wen Jianguo, Kong Zhijie, Shan Shiyao, Vargas Jorge A, Yan Shan, Hopkins Emma, Park Keonwoo, Sharma Anju, Ren Yang, Petkov Valeri, Wang Lichang, Zhong Chuan-Jian
Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, USA.
Key Laboratory of Ministry of Education for Green Chemical Technology, Tianjin University, Tianjin, China.
Nat Commun. 2021 Feb 8;12(1):859. doi: 10.1038/s41467-021-21017-6.
Alloying noble metals with non-noble metals enables high activity while reducing the cost of electrocatalysts in fuel cells. However, under fuel cell operating conditions, state-of-the-art oxygen reduction reaction alloy catalysts either feature high atomic percentages of noble metals (>70%) with limited durability or show poor durability when lower percentages of noble metals (<50%) are used. Here, we demonstrate a highly-durable alloy catalyst derived by alloying PtPd (<50%) with 3d-transition metals (Cu, Ni or Co) in ternary compositions. The origin of the high durability is probed by in-situ/operando high-energy synchrotron X-ray diffraction coupled with pair distribution function analysis of atomic phase structures and strains, revealing an important role of realloying in the compressively-strained single-phase alloy state despite the occurrence of dealloying. The implication of the finding, a striking departure from previous perceptions of phase-segregated noble metal skin or complete dealloying of non-noble metals, is the fulfilling of the promise of alloy catalysts for mass commercialization of fuel cells.
将贵金属与非贵金属合金化能够在降低燃料电池中电催化剂成本的同时实现高活性。然而，在燃料电池运行条件下，目前最先进的氧还原反应合金催化剂要么具有高原子百分比的贵金属（>70%），但其耐久性有限，要么在使用较低百分比的贵金属（<50%）时表现出较差的耐久性。在此，我们展示了一种通过将PtPd（<50%）与3d过渡金属（Cu、Ni或Co）以三元组成合金化而得到的高耐久性合金催化剂。通过原位/操作条件下的高能同步加速器X射线衍射结合原子相结构和应变的对分布函数分析，探究了高耐久性的起源，揭示了再合金化在压缩应变单相合金状态下的重要作用，尽管发生了脱合金化。这一发现与之前对相分离贵金属表层或非贵金属完全脱合金化的认知截然不同，其意义在于实现了合金催化剂推动燃料电池大规模商业化的前景。
