材料科学
退火(玻璃)
双金属片
钴
催化作用
扫描透射电子显微镜
透射电子显微镜
四方晶系
纳米晶
化学工程
感应耦合等离子体
热稳定性
纳米技术
分析化学(期刊)
金属
结晶学
晶体结构
等离子体
化学
冶金
物理
工程类
量子力学
生物化学
色谱法
作者
Jennifer D. Lee,Davit Jishkariani,Yingrui Zhao,Stan Najmr,Daniel J. Rosen,James M. Kikkawa,Eric A. Stach,Christopher B. Murray
标识
DOI:10.1021/acsami.9b06346
摘要
The development of a suitable catalyst for the oxygen reduction reaction (ORR), the cathode reaction of proton exchange membrane fuel cells (PEMFC), is necessary to push this technology toward widespread adoption. There have been substantial efforts to utilize bimetallic Pt−M alloys that adopt the ordered face-centered tetragonal (L10) phase in order to reduce the usage of precious metal, enhance the ORR performance, and improve catalyst stability. In this work, monodisperse Pt–Co nanocrystals (NCs) with well-defined size (4–5 nm) and cobalt composition (25–75 at%) were synthesized via colloidal synthesis. The transformation from the chemically disordered A1 (face-centered cubic, fcc) to the L10 phase was achieved via thermal annealing using both a conventional oven and a rapid thermal annealing process. The structure of the Pt–Co catalysts was characterized by a variety of techniques, including transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy in high-angle annular dark-field scanning transmission electron microscopy (STEM-EDS), small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), and inductively coupled plasma–optical emission spectrometry (ICP-OES). The effects of annealing temperature on the composition-dependent degree of ordering and subsequent effect on ORR activity is described. This work provides insights regarding the optimal spatial distribution of elements at the atomic level to achieve enhanced ORR activity and stability.
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