Bamboo-like Carbon Nanotube/Fe3C Nanoparticle Hybrids and Their Highly Efficient Catalysis for Oxygen Reduction

The design of a new class of non-noble-metal catalysts with oxygen reduction reaction (ORR) activity superior to that of Pt is extremely important for future fuel cell devices. Here we demonstrate a one-pot, large-scale protocol for the controlled synthesis of new one-dimensional bamboo-like carbon nanotube/Fe3C nanoparticle hybrid nanoelectrocatalysts, which are directly prepared by annealing a mixture of PEG-PPG-PEG Pluronic P123, melamine, and Fe(NO3)3 at 800 °C in N2. The resulting hybrid electrocatalysts show very high ORR activity with a half-wave potential of 0.861 V (vs reversible hydrogen electrode) in 0.10 M KOH solution, 49 mV more positive than that of 20 wt% Pt/C catalyst. Furthermore, they exhibit good ORR activity in acidic media, with an onset potential comparable to that of the Pt/C catalyst. Most importantly, they show much higher stability and better methanol tolerance, with almost no ORR polarization curve shift and no change of the oxygen reduction peak in the cyclic voltammogram in the presence of 1.0 M methanol, than those of the commercial Pt/C catalyst in both alkaline and acidic solutions. This makes them one of the best non-noble-metal catalysts ever reported for ORR in both alkaline and acidic solutions.