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

Xiong Peng,Varchaswal Kashyap,John Varcoe,Lianqin Wang,Sreekumar Kurungot,Benjamin Ng,William Mustain

doi:10.3390/catal9030264

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.

Highlights

To enable a shift away from fossil fuels to clean-energy alternatives with reduced environmental impact, it is important to search for safe, efficient and economical energy conversion technologies that can be commercialized
The broad commercialization of proton exchange membrane fuel cell (PEMFC) has been hindered by high cost, which is partially caused by the use of platinum group metal (PGM) catalysts at both the anode and cathode [1]
The ferrite nanoparticles were spherical in structure and well distributed

Summary

Introduction

To enable a shift away from fossil fuels to clean-energy alternatives with reduced environmental impact, it is important to search for safe, efficient and economical energy conversion technologies that can be commercialized. Fuel cells are electrochemical devices that directly convert stored chemical energy into electricity with high efficiency. They have received a significant amount of attention for many applications, including transportation, where the proton exchange membrane fuel cell (PEMFC). Anion exchange membrane fuel cells (AEMFCs) have been proposed as a potentially lower-cost alternative to PEMFCs. It is believed that the alkaline electrolyte would make it possible to use non-PGM electrocatalysts from a broader selection of materials that are unstable in acid as well as enable lower cost hardware and membranes. It is believed that the alkaline electrolyte would make it possible to use non-PGM electrocatalysts from a broader selection of materials that are unstable in acid as well as enable lower cost hardware and membranes

Methods

Results

Conclusion