Synergistic Fe-Si Dual-Site Pathway Engineering in Biomass-Derived Carbon Matrix for High-Performance Oxygen Reduction Reaction

Abstract

Anion exchange membrane fuel cells (AEMFCs) offer a sustainable energy solution with non-precious metal catalysts, reduced degradation, and fuel flexibility. However, the sluggish oxygen reduction reaction (ORR) at the cathode and durability concerns impede commercialization. To address these challenges, this study presents a dual-atomic SiFe–N–C catalyst derived from pinecones, a naturally abundant biomass resource. The catalyst features a nitrogen-rich porous carbon matrix that stabilizes Si–Fe dual-atomic sites during pyrolysis. Advanced analyses confirm Fe–Si and Fe–N bonds, which synergistically enhance ORR activity by optimizing electronic structures and intermediate adsorption energies. The SiFe–N–C catalyst surpasses Pt/C and Fe–N–C single-atom benchmarks with superior ORR activity and excellent long-term durability supported by high resistance to CO poisoning as well as methanol crossover. It also demonstrates a promising electrochemical performance as a catalytic material for the separator of Li–S battery. Mechanistic studies reveal that the Si–Fe dual-atomic configuration promotes an efficient Fe–O–O–Si pathway, reducing energy barriers and offering a cost-effective, high-performance solution for electrochemical energy conversion and storage applications.