Nitrogen-doped and nanostructured carbons with high surface area for enhanced oxygen reduction reaction

The development of highly-efficient, inexpensive, and stable electrocatalysts as alternatives to platinum-based materials for the oxygen reduction reaction (ORR) is crucial to various energy storage and conversion systems, such as metal–air batteries and fuel cells. Herein, we have successfully prepared three kinds of hierarchically porous nitrogen-doped carbons with different morphologies (particles, nanowires, and nanoribbons) through a carbon dioxide activation process. The porous properties and catalytic performance of the nitrogen-doped porous carbons are dramatically and clearly improved through changing the morphology of polypyrrole precursors. Among these nitrogen-doped porous carbons, the nitrogen-doped and nanostructured carbon with the morphology of nanoribbons possesses the highest specific surface area (1130 m2 g−1) and displays the best ORR activity with the largest electron transfer number (3.67) and the most positive onset potential (0.86 V vs. RHE) in oxygen-saturated aqueous KOH solution (0.1 M). This enhanced ORR performance can be attributed to nitrogen-doping, a hierarchically porous structure, and large specific surface area. [Display omitted]