Preparation of nitrogen-doped carbon nanotube arrays and their catalysis towards cathodic oxygen reduction in acidic and alkaline media

Nitrogen-doped carbon nanotube (N-CNT) arrays were prepared by chemical vapor deposition, using ferrocene as the catalyst precursor and imidazole as the carbon and nitrogen precursor. For the reduction of oxygen, the N-CNTs showed excellent electrocatalytic activity in both acidic and alkaline media. The N-CNTs were characterized by scanning and transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and elemental analysis. The samples had a high nitrogen content (8.54 at.%) and a bamboo-like structure, and their activity varied according to the amount of pyridinic nitrogen they contained.