Heteroatom‐Doped Carbon Nanotubes as Advanced Electrocatalysts for Oxygen Reduction Reaction

Efficient oxygen reduction reaction (ORR) catalysts play a key role in the development of electrochemical energy devices, such as fuel cells and metal-air batteries. In order to replace or reduce the usage of the precious Pt-based ORR catalysts, carbon nanotubes (CNTs) have recently been explored as efficient ORR electrocatalysts due to their unique electrical and thermal properties, wide availability, corrosion resistance, and large surface area. In particular, the electrocatalytic activities of CNTs can be significantly enhanced by heteroatom doping, especially nitrogen doping. This chapter focuses on recent progresses in the development of doped CNTs as advanced ORR electrocatalysts. An emphasis is placed on recent breakthroughs in the design and development of various heteroatom (e.g., N, B, P, and S)-doped CNTs with high electrocatalytic activities, along with the experimental observation and fundamental understanding of the active sites and catalytic mechanism for ORR.