High-Performing PGM-Free AEMFC Cathodes from Carbon-Supported Cobalt Ferrite Nanoparticles

Abstract

Efficient and durable non-precious metal electrocatalysts for the oxygen reduction reaction (ORR) are highly desirable for several electrochemical devices, including anion exchange membrane fuel cells (AEMFCs). Here, cobalt ferrite (CF) nanoparticles supported on Vulcan XC-72 carbon (CF-VC) were created through a facile, scalable solvothermal method. The nano-sized CF particles were spherical with a narrow particle size distribution. The CF-VC catalyst showed good ORR activity, possessing a half-wave potential of 0.71 V. Although the intrinsic activity of the CF-VC catalyst was not as high as some other platinum group metal (PGM)-free catalysts in the literature, where this catalyst really shined was in operating AEMFCs. When used as the cathode in a single cell 5 cm−2 AEMFC, the CF-VC containing electrode was able to achieve a peak power density of 1350 mW cm−2 (iR-corrected: 1660 mW cm−2) and a mass transport limited current density of more than 4 A cm−2 operating on H2/O2. Operating on H2/Air (CO2-free), the same cathode was able to achieve a peak power density of 670 mW cm−2 (iR-corrected: 730 mW cm−2) and a mass transport limited current density of more than 2 A cm−2. These peak power and achievable current densities are among the highest reported values in the literature to date.