Advanced Free Radical Scavenger for Proton Exchange Membrane Fuel Cells

Yttrium doped cerium oxide (CeO 2 ·Y 2 O 3 ) was studied as a free radical scavenger for proton exchange membrane fuel cells (PEMFCs). The CeO 2 ·Y 2 O 3 was compared with pure CeO 2 in MEAs with and without the free radical scavenger. Membrane Electrode assembly (MEA) after open circuit voltage (OCV) hold accelerated stress test (AST) show better performance retention with CeO 2 ·Y 2 O 3 than CeO 2 . CeO 2 ·Y 2 O 3 and CeO 2 show slightly improved performance than pristine MEA without free radical scavenger. X-ray fluorescence (XRF) confirmed the improved Ce ions retention with CeO 2 ·Y 2 O 3 than pure CeO 2 , indicating improved stability of CeO 2 after doping with Yttrium. Furthermore, ex-situ Fenton study with inductively coupled plasma mass spectrometry (ICP-MS) analysis shows better stability of Ce in CeO 2 ·Y 2 O 3 . This study shows that yttrium-doped cerium oxide has better stability against dissolution and enhances the stability of polymer components against free radicals than CeO 2 .