Influence of gas environment and heating on atomic structures of platinum nanoparticle catalysts for proton-exchange membrane fuel cells

Kenta Yoshida, Xudong Zhang, Yusuke Shimada, Yasuyoshi Nagai, Tomoki Hiroyama, Nobuo Tanaka, Leonardo Lari, Michael R. Ward, Edward D. Boyes, Pratibha L. Gai

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Atomic-scale relaxations of platinum nanoparticles (Pt NPs) for fuel-cell catalysts are evaluated by spherical-aberration corrected environmental transmission electron microscopy (ETEM) under reference high-vacuum and N 2 atmospheres, and then under reactive H 2 , CO and O 2 atmospheres, combined with ex situ durability test using an electrochemical half-cell. In high-vacuum, increasing roughness due to continuous relaxation of surface-adsorbed Pt atoms is quantified in real-space. Under H 2 and N 2 atmospheres at a critical partial pressure of 1 ×10 -2 Pa the stability of the surface facets is for the first time found to be improved. The adsorption behaviour of CO molecules is investigated using experimentally measured Pt-Pt bond lengths on the topmost surface layer of Pt NPs. The deactivation of Pt NPs in the anode environment of a proton-exchange-membrane fuel-cell is demonstrated at the atomic-scale in the ETEM, and the transformation of NPs into disordered nanoclusters is systematically quantified using the partial size distribution of Pt atomic clusters under controlled heating experiments at 423, 573 and 723 K.

Original languageEnglish
Article number175701
JournalNanotechnology
Volume30
Issue number17
DOIs
Publication statusPublished - 2019

Keywords

  • Environmental transmission electron microscopy
  • catalysts
  • in situ
  • nanoparticle
  • surface

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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