A Highly Efficient Electrocatalyst Derived from Polyaniline@CNTs−SPS for the Oxygen Reduction Reaction

It is of vital importance to develop novel low-cost and high-efficiency electrocatalysts towards oxygen reduction reaction (ORR), which play a considerable impact on electrochemical energy conversion and storage devices, such as fuel cells and metal-air batteries. In this work, we demonstrate a kind of highly active nitrogen-doped carbons with uniform hierarchical structures through sulfonated polystyrene regulating the distribution of PANI covering on CNTs, prepared by a reliable and controllable route. The as-prepared electrocatalyst shows outstanding activity towards ORR in alkaline media, manifesting comparable or even better performance compared to the commercial Pt/C. The optimized nitrogen-doped CNTs exhibits an onset potential (Eonset) of 0.94 V (vs. reversible hydrogen electrode (RHE)) and half-wave potential (E1/2) of 0.83 V (vs. RHE) in 0.1 M KOH with superior stability, durability and methanol tolerance, suggesting their promising applications in fuel cells and metal-air batteries. The significantly improved electrochemcal properties demonstrate the unique sulfonated polystyrene layer anchoring on the surface of CNTs in the as-designed PANI@CNTs-SPS contributes to uniform distribution of nitrogen sites of the catalyst.