Comparative study of different carbon-supported Fe₂O₃-Pt catalysts for oxygen reduction reaction

One of the challenges in electrocatalysis is the adequate dispersion of the catalyst on an appropriate porous support matrix, being up to now the most commonly used the carbon-based supports. To overcome this challenge, carbon supports must first be functionalized to guide the catalyst's nucleation, thereby, improving the dispersion and allowing the use of smaller amount of the catalyst material to achieve a higher electrochemically active surface area. This study present the effect of functionalized Vulcan carbon XC72 (FVC) and functionalized Black Pearl carbon (FBPC) as supports on the catalytic activity of decorated Fe₂O₃ with Pt. Both carbons were functionalized with HNO₃ and subsequently treated with ethanolamine. Fe₂O₃ nanoparticles were synthesized by chemical reduction and decorated with platinum by epitaxial growth. Pt and Fe₂O₃ structural phases were identified by XRD and XPS; the Pt content was measured by XPS, and results showed to a high Pt content in Fe₂O₃-Pt/FBPC. TEM micrographs reveal nanoparticles with an average size of 2 nm in both supported catalysts. The Fe₂O₃-Pt/FVC catalyst presents the highest specific activity and mass activity, 0.21 mA cm^-2_Pt and 140 mA mg_Pt^-1, respectively, associated to the appropriate distribution of platinum on the Fe₂O₃ nanoparticles.