The Understanding of the Improved Catalytic Performance of Steam-Activated Fe-N-C Catalyst for Alkaline Hydrazine Fuel Cell

Abstract

Fe-N-C materials are currently the most promising non-noble-metal-based ORR electrocatalyst, but their low density of surface active sites compared with Pt/C necessitates improving their utilization via porous structures. Previously, we studied modified Fe-N-C catalyst for the oxygen reduction reaction (ORR) in the cathodes of alkaline hydrazine liquid fuel cells (AHFC). Fe-N-C with magnetite particles and hierarchical pore structure was prepared by steam activation. The steam activation process significantly improves the power performance of the AHFC as indicated by the lower IR and activation voltage losses. The steam activation transformed the Fe3C nanoparticles in Fe-N-C into larger Fe3O4 particles, which caused the electrode surface to become more hydrophilic. Here, elimination of the Fe3O4 nanoparticles by acid leaching was conducted to investigate the effect of Fe3O4 nanoparticles, resulting in enhancing power performance for alkaline hydrazine liquid fuel cells.