Chinese Journal of Catalysis ›› 2020, Vol. 41 ›› Issue (5): 807-812.DOI: 10.1016/S1872-2067(19)63451-0

• Special Column on Electrocatalysis • Previous Articles     Next Articles

Interatomic diffusion in Pd-Pt core-shell nanoparticles

Yanfeng Zhanga,b,c, Shangqian Zhub, Lili Zhangb,d, Dong Sue, Minhua Shaob   

  1. a Jiangsu Aoxin NEV Co., Ltd, Yancheng, Jiangsu, China;
    b Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China;
    c Shanghai AI NEV Innovative Platform Co., Ltd, Shanghai, China;
    d Jiangsu Key Laboratory for Chemistry of Low-Dimension Materials, Huaiyin Normal University, Huaian 223300, Jiangsu, China;
    e Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA
  • Received:2019-08-22 Revised:2019-10-11 Online:2020-05-18 Published:2019-12-31
  • Contact: S1872-2067(19)63451-0
  • Supported by:
    The authors acknowledge the support from Jiangsu High-level Innovation and Entrepreneurship Talent Plan in 2017, National Key R&D Program of China (2017YFB0102900), and Research Grant Council (26206115 and 16304117) of the Hong Kong Special Administrative Region, and Guangdong Special Fund for Science and Technology Development (Hong Kong Technology Cooperation Funding Scheme (201604030012, 201704030065).

Abstract: Pt monolayer-based core-shell catalysts have garnered significant interest for the application of low temperature fuel cell technology as their use may enable a decreased loading of Pt while still providing sufficient current density to meet volumetric requirements. One promising candidate in this class of materials is a Pd@Pt core-shell catalyst, which shows enhanced activity toward oxygen reduction reaction (ORR). One concern with the use of Pd@Pt, however, is the durability of the core-shell structure as Pd atoms are thermodynamically favored to migrate to the surface. The pathway of the migration has not been systematically studied. The current study explores the stability of this structure to thermal annealing and probes the effect of this heat treatment on the catalyst surface structure and its oxygen reduction activity. It was found that surface alloying between Pd and Pt occurs at temperatures as low as 200℃, and significantly alters the structure and ORR catalytic activity in the range of 200-300℃. Our results shed lights on the thermal induced interatomic diffusion in all core-shell and thin film structures.

Key words: Monolayer, Proton exchange membrane fuel cell, Stability, Interatomic-diffusion, Electrocatalysis