Kinetic Study and Fuel Cell Testing for a Hybrid of Fourteen-Membered Macrocyclic Fe Complex and Fe/N/C Nano-Catalyst

The development of nonprecious metal (NPM) catalysts for oxygen reduction is critical to advancing the widespread adoption of fuel cells. Among NPM catalysts, single-atom catalysts derived from the pyrolysis of Fe, N, and C-containing precursors are well-known for their activity. Additionally, 14-membered macrocyclic Fe complexes have garnered significant attention for their catalytic potential. In this study, we investigated a hybrid catalyst comprising a 14-membered macrocyclic Fe complex and an Fe/N/C catalyst synthesized via the pyrolysis of Fe-containing polyimide nanoparticles as an NPM oxygen reduction catalyst. Kinetic studies conducted using rotating ring-disk electrode (RRDE) voltammetry in both acidic and alkaline media revealed that this hybrid catalyst exhibits exceptional activity. Furthermore, fuel cell tests with a proton exchange membrane demonstrated promising performance, highlighting the potential of this hybrid approach for practical applications.