Highly Active and Durable Metal-Free Carbon Catalysts for Anion-Exchange Membrane Fuel Cells

Abstract

The development of highly active and durable platinum-free oxygen reduction reaction (ORR) catalysts is of vital importance for the practical application of anion-exchange membrane fuel cells (AEMFCs). Herein, a metal-free carbon catalyst (marked as NDPC-1000) with a graphitic N-regulating defect structure is specifically designed and developed for AEMFCs by integrating theoretical calculations and experiments. Density functional theory calculations first reveal that the graphitic N can tailor the charge density of pentagon and armchair defects to reach the top of the adsorption energy-activity volcano plot, while the enhanced durability is attributed to the high dissociation energy of the C N covalent bond. Under this guidance, the synthesized NDPC-1000 demonstrates its high ORR activity and durability in alkaline media. With H2/O2 reacting gases, the AEMFC with this catalyst as the cathode delivers a peak power density of 913 mW cm−2. Unprecedented fuel cell durability is verified via continuous operation over 100 h at 0.25 A cm−2 with only a voltage decay of ≈25%, which is the greatest among all reported metal-free-based AEMFCs. Here a theory-guided experiment strategy is provided for the development of high-performance and durable ORR catalysts for AEMFCs.