Advanced Metal-Phthalocyanine-Based Catalysts with Enhanced Oxygen Reduction Reaction Activity for High-Performance Anion-Exchange Membrane Fuel Cells

Abstract Metal phthalocyanine (MPc)-based catalysts offer a structurally tunable platform for the oxygen reduction reaction (ORR) in alkaline media, yet their application in anion-exchange membrane fuel cells (AEMFCs) has been limited by insufficient performance. Here, we report two iron tetra-azaphthalocyanine catalysts, AZ-FT-30 and AZ-FO-30, evaluated in AEMFCs. Both catalysts exhibit comparable electrochemical surface areas (∼156–158 m2 g–1), enabling isolation of intrinsic activity. AZ-FO-30 demonstrates better catalyst activity toward alkaline ORR and enhanced cathode performance, achieving a peak power density of 902 mW cm–2 under H2–O2 conditions, representing the highest reported value for MPc-based AEMFC cathodes to date. Notably, the AZ-FO-30-based cell sustains stable operation over 35 h at 400 mA cm–2 with a minimal voltage decay (2.4 mV h–1), demonstrating the capability of MPc systems to achieve extended device-level durability. Density functional theory calculations demonstrate that AZ-FO-30 exhibits the shortest Fe–O bond distance, indicative of the strongest OH adsorption at the Fe active site, a trend consistently observed with the model containing one explicit water molecule, confirming its good adsorption characteristics. These findings demonstrate that targeted modification of the phthalocyanine framework enables the development of high-performance and durable cathode materials for platinum-group metal-free AEMFCs.