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

摘要

The development of highly active and durable platinum-free oxygen reductionreaction (ORR) catalysts is of vital importance for the practical applicationof anion-exchange membrane fuel cells (AEMFCs). Herein, a metal-freecarbon catalyst (marked as NDPC-1000) with a graphitic N-regulating defectstructure is specifically designed and developed for AEMFCs by integratingtheoretical calculations and experiments. Density functional theory calculationsfirst reveal that the graphitic N can tailor the charge density of pentagonand armchair defects to reach the top of the adsorption energy-activityvolcano plot, while the enhanced durability is attributed to the high dissociationenergy of the C-N covalent bond. Under this guidance, the synthesizedNDPC-1000 demonstrates its high ORR activity and durability in alkalinemedia. With H_2/O_2 reacting gases, the AEMFC with this catalyst as thecathode delivers a peak power density of 913 mW cm~(?2). Unprecedented fuelcell 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 reportedmetal-free-based AEMFCs. Here a theory-guided experiment strategy is providedfor the development of high-performance and durable ORR catalysts forAEMFCs.