Nitrogen-Doped Carbon Nanocages as Efficient Metal-Free Electrocatalysts for Oxygen Reduction Reaction

摘要

The oxygen reduction reaction (ORR) is one of the most crucial factors limiting the performance of proton exchange membrane fuel cells due to its slow kinetics. The development of efficient ORR electrocatalysts is thus of great significance. Today, platinum is usually used as the electrocatalyst for ORR; however, the large-scale application of fuel cells is hampered by the its scarcity and high cost. In addition, Pt-based catalyst is sensitive to deactivation in the presence of CO, methanol and also susceptible to time-dependent drift Hence, great efforts have been devoted to exploring the advanced ORR catalysts to rival the commercial Pt/C catalyst in activity and durability with reduced Pt loading, or nonprecious metals, or even metal-free species. Compared to Pt-based catalysts, metal-free catalysts have several noteable advantages, in that they do not suffer CO poisoning or crossover effects, have long-term operational stability, and are relatively cost-effective. Following the breakthrough in discovering the metal-free catalyst of PEDOT for ORR, heteroatom-doped carbon nanotubes (CNTs) were demonstrated to be a new kind of promising metal-free electro-catalyst.