Pd-Pt nanoparticles combined with ceria nanorods for application in oxygen reduction reactions in alkaline direct ethanol fuel cell cathodes

Abstract

Fuel cells are important energy conversion devices. However, challenges in this regard are still noted, such as low electrocatalyst efficiencies in the oxygen reduction reaction (ORR), which occurs slowly in electrocatalyst cathodes. In this sense, this study aimed to synthetize hybrid binary and ternary electrocatalysts formed by palladium and platinum alloy nanoparticles and ceria nanorods (CeO2 NR) supported on carbon black Vulcan XC-72 (PdxPty/Vn and (Pd3Pt1)x(CeO2 NR)y(Vn)z) for the study of the oxygen reduction reaction (ORR) and application as alkaline direct ethanol fuel cells (ADEFCs) cathodes. The binary and ternary hybrid electrocatalysts were characterized using different physicochemical and electrochemical techniques. The ternary hybrid electrocatalyst, (Pd3Pt1)15(CeO2 NR)10(Vn)75, reached higher open circuit voltage (OCV), maximum current and power densities, of 1.13 V, 219 mA cm-2 and 61 mW cm-2, respectively, compared to the commercial Pt/C Alfa Aesar (AA) and other evaluated electrocatalysts. The ternary hybrid electrocatalyst, (Pd3Pt1)15(CeO2 NR)10(Vn)75, is interesting for application as an ADEFC cathode targeting the ORR, due to an almost 3-fold maximum power density and almost twice the maximum current density compared to a commercial electrocatalyst with the same noble metal loading, explained by increased defects and oxygenated species in this electrocatalyst as revealed by Fourier Transform Infrared Spectroscopy (FT-IR) and Raman analyses.