Impact of Sonication Treatment on Physicochemical Properties of Carbon Blacks and Pt/C Catalysts in Proton Exchange Membrane Fuel Cells

Abstract Here the chemical and structural effects of ultrasonic dispersion on carbon blacks (CBs), Pt/C catalysts, and their performance in proton exchange membrane fuel cells (PEMFC) are investigated. Ultrasound treatment induces material‐specific chemical modifications, with low and medium surface area CBs (C65, XC72R) exhibiting increased oxidation, while high surface area CBs remain largely unaffected. Changes in isoelectric point and functional groups confirm these variations. Performance analysis before sonication follows the trend: Pt/high surface area carbon (HSAC) = Pt/medium surface area carbon (MSAC) > Pt/XC72R, primarily influenced by charge‐transfer resistance. After ultrasound treatment, the ranking shifts to Pt/HSAC > Pt/MSAC > Pt/XC72R, indicating that sonication mainly affects the Pt/C interface rather than bulk conductivity. While Pt/HSAC retains stability, Pt/MSAC and Pt/XC72R suffer performance degradation due to oxidation, structural changes, and platinum (Pt) detachment. These findings underscore the necessity of tailored dispersion protocols for different carbon blacks. High‐energy sonication may degrade certain CBs and Pt/C catalysts (e.g., Pt/MSAC, Pt/XC72R), whereas Pt/HSAC remains robust, serving as a benchmark for future catalyst development. The study establishes a systematic framework correlating CB properties with PEMFC performance, highlighting the role of surface functionalization in optimizing catalyst dispersion strategies.