ETEM observation of Pt/C electrode catalysts in a moisturized cathode atmosphere

Electron Microscopy and Analysis Group Conference 2013

Yoshida, K.^1,2 ; Zhang, X.^2,3 ; Tanaka, N.^2,3 ; Boyes, E.D.^4 ; Gai, P.L.^5

Institute for Advanced Research, Nagoya University, Chikusa-ku, Nagoya, 4648603, Japan^1

Nanostructures Research Laboratory, Japan Fine Ceramics Center, Atsuta-ku, Nagoya 456-8587, Japan^2

Department of Crystalline Materials Science, Ecotopia Science Institute, Nagoya University, Chikusa-ku, 464-8603 Nagoya, Japan^3

Departments of Physics and Electronics, York JEOL Nanocentre, University of York, Heslington, YO10 5DD York, United Kingdom^4

Departments of Chemistry, York JEOL Nanocentre, University of York, Heslington, YO10 5DD York, United Kingdom^5

关键词: Deactivation process;    Environmental transmission electron microscopy;    High speed ccd cameras;    Oxygen reduction reaction;    Platinum nano-particles;    Proton exchange membrane fuel cell (PEMFCs);    Pure nitrogen atmosphere;    Spherical aberrations;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/522/1/012007/pdf
DOI  :  10.1088/1742-6596/522/1/012007

来源: IOP

【 摘 要 】

There have been reports of challenges in designing platinum carbon (Pt/C) electrode catalysts for PEMFC. Pt/C electrode catalysts deactivate much faster on the cathode (in moisturized O2) than on the anode (in H2). To understand influences of moisture and oxygen on the deactivation of the Pt/C catalysts in proton-exchange-membrane fuel cells (PEMFCs), spherical-aberration-corrected environmental transmission electron microscopy (AC-ETEM) was applied with a high-speed CCD camera. Structural changes of the Pt/C electrode catalysts were dynamically recorded in moisturized nitrogen, oxygen and hydrogen. The mass spectrometry confirmed the moisture content (between 5 to 30 %) of nitrogen driving gas through a humidifier. Coalescence of platinum nanoparticles (D 3.24 nm) was carefully evaluated in pure N2and moisturized N2atmosphere. The Pt/C showed considerable structural weakness in a moisturized N2 atmosphere. Comparable results obtained by AC-ETEM in different gas atmospheres also suggested ways to improve the oxygen reduction reaction (ORR). In this paper, the deactivation process due to moisture (hydroxylation) of carbon supports is discussed using for comparison the movement of platinum nanoparticles measured in moisturized nitrogen and pure nitrogen atmospheres.