Wu Zhi-Peng, Dinh Dong, Maswadeh Yazan, Caracciolo Dominic T, Zhang Hui, Li Tianyi, Vargas Jorge A, Madiou Merry, Chen Cailing, Kong Zhijie, Li Zeqi, Zhang Huabin, Ruiz Martínez Javier, Lu Susan S, Wang Lichang, Ren Yang, Petkov Valeri, Zhong Chuan-Jian
Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States.
Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
J Am Chem Soc. 2024 Dec 25;146(51):35264-35274. doi: 10.1021/jacs.4c12550. Epub 2024 Dec 10.
Understanding the structure evolution of nanoalloys under reaction conditions is vital to the design of active and durable catalysts. Herein, we report an operando measurement of the dynamic lattice strains of dual-noble-metal alloyed with an earth-abundant metal as a model electrocatalyst in a working proton-exchange membrane fuel cell using synchrotron high-energy X-ray diffraction coupled with pair distribution function analysis. The results reveal an interfacial reaction-triggered oscillatory lattice strain in the alloy nanoparticles upon surface dealloying. Analysis of the lattice strains with an apparent oscillatory irregularity in terms of frequency and amplitude using time-frequency domain transformation and theoretical calculation reveals its origin from a metal atom vacancy diffusion pathway to facilitate realloying upon dealloying. This process, coupled with surface metal partial oxidation, constitutes a key factor for the nanoalloy's durability under the electrocatalytic oxygen reduction reaction condition, which serves as a new guiding principle for engineering durable or self-healable electrocatalysts for sustainable fuel cell energy conversion.
了解纳米合金在反应条件下的结构演变对于设计活性和耐用催化剂至关重要。在此，我们报告了一种操作测量方法，该方法利用同步加速器高能X射线衍射结合对分布函数分析，对作为模型电催化剂的双贵金属与一种储量丰富的金属合金化后的动态晶格应变进行了原位测量，该模型电催化剂应用于工作中的质子交换膜燃料电池。结果表明，在表面脱合金化过程中，合金纳米颗粒中存在界面反应引发的振荡晶格应变。利用时频域变换和理论计算对晶格应变在频率和幅度方面明显的振荡不规则性进行分析，揭示了其起源于金属原子空位扩散途径，以促进脱合金化后的再合金化。这一过程与表面金属部分氧化相结合，构成了纳米合金在电催化氧还原反应条件下耐久性的关键因素，这为设计用于可持续燃料电池能量转换的耐用或自修复电催化剂提供了新的指导原则。
