Durability of Platinum-Based Carbon-Supported Electrocatalysts in Liquid Versus Solid Polymer Alkaline Electrolytes
Abstract
Alkaline fuel cells (AFC) are competitors to proton-exchange membrane fuel cells for stationary applications [1]. Because many metals and metal oxides are stable at high pH [2], one may think that AFC electrocatalysts will be more stable in operation than in acidic medium. However, this was proven wrong for carbon-supported Pt and Pd nanoparticles (NPs) aged in liquid alkaline environment: these undergo severe electrochemical surface area losses even for a very mild potential cycling procedure in 0.1 M NaOH [3, 4]. Identical-location transmission electron microscopy (ILTEM) experiments revealed pronounced detachment of the Pt (and Pd) NPs from the carbon support, but minor degradation phenomena for the metal NPs and the carbon support itself. Additional experiments performed in various alkaline electrolytes (LiOH, NaOH, KOH, CsOH) coupled with in situ Fourier-transform infrared spectroscopy enabled to link this detachment to the formation of solid carbonates at the interface between the Pt (Pd) NPs and the carbon support, because the metal nanoparticles assist the local corrosion of the carbon support (firstly into CO2, then CO3 2- anions and finally into M2CO3, M = Li, Na, K or Cs).
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 13, 2018
- Source ID
- 10.1149/ma2018-01/30/1778
Entities
People
- Clémence Lafforgue
- Dario R Dekel
- Frédéric Maillard
- Laetitia Dubau
- Marian Chatenet