Gram-scale production of an Fe single atom catalyst and mass transfer enhancement in PEMFCs

Abstract

The huge advantage of the lower fabrication cost for non-Pt catalysts is attracting increasing attention for fuel cell development. As a potential candidate, Fe single atom (SA) catalysts exhibit remarkable catalytic activity for the oxygen reduction reaction. However, due to the relatively low intrinsic activity, high active site density and an optimized mass transfer path are particularly required for Fe-SA proton exchange membrane fuel cells (PEMFCs). Herein, a Fe-SA catalyst with abundant heteroatoms and a large specific surface area is synthesized based on a lab-made ZIF-derived carbon support via a simple adsorption-annealing method. Benefitting from the advanced carbon support, plenty of Fe atoms can be adsorbed and anchored on the surface of the carbon particles. After careful modulation of the annealing temperature, highly dispersed Fe single atom active sites can be obtained, leading to good catalytic activity (the half-wave potential is more than 0.827 V versus RHE). Furthermore, coordinated with the structure optimization of the gas diffusion layer, the maximum power density can be improved to 803 mW cm⁻², indicating the application potential of this catalyst in PEMFCs. This work not only obtains an advanced Fe-SA ORR catalyst but also provides a demonstration for the research and development of non-Pt fuel cell catalysts.