Stability of supported Pd-based ethanol oxidation reaction electrocatalysts in alkaline media.

[Display omitted] • Electrochemical online ICP-MS is used to assess time and potential resolved Pd dissolution. • Accelerated stress tests are developed to test catalyst stability in RDE. • The catalysts containing Sn and Fe demonstrate improved activity and maintain good stability. • PdSn/C and PdFe 3 O 4 /C are suitable for fuel cell applications, Nb dissolution destabilizes Pd. • Additional metals and oxides can improve the alcohol oxidation kinetics of Pd. This study evaluates the dissolution of the supported electrocatalysts Pd/C, PdSn/C, PdNb/C, and PdFe 3 O 4 /C during ethanol oxidation reaction for Alkaline Direct Liquid Fuel Cells (ADLFC) applications. A scanning flow cell (SFC) combined to an inductively coupled plasma mass spectrometry (online ICP-MS) is used to assess the dissolution stability in a broad potential window. Accelerated stress tests with and without ethanol are developed using a rotating disk electrode (RDE) with dissolution products analysis by ex-situ ICP-MS. Potential profiles simulating those experienced by the catalyst during regular fuel cell operation were used. Sn and Fe catalysts demonstrate improved activity and stability compared with the material with Pd alone. For these reasons, PdSn/C and PdFe 3 O 4 /C are suitable for ADLFC applications. Severe Nb dissolution destabilizes Pd, increasing its leaching. This work demonstrates that while additional metals and oxides can improve the alcohol oxidation kinetics of Pd, these additives' dissolution stability must already be considered at the catalyst design stage. [ABSTRACT FROM AUTHOR]