Self‐Sacrificial Template Synthesis of a Nitrogen‐Doped Microstructured Carbon Tube as Electrocatalyst for Oxygen Reduction

Abstract The development of low‐cost, efficient and stable electrocatalysts for the oxygen reduction reaction (ORR) is desirable but remains a great challenge. We report a self‐sacrificial template synthesis approach for nitrogen‐doped hollow carbon microtubes as electrocatalyst for ORR. Typically, Fe‐MIL (Materiaux de l'Institute Lavosier) nanocrystals cast as self‐sacrificial template. Polyaniline (PANI) was in situ‐synthesized and deposited on the surface of Fe‐MIL nanocrystals. By a two‐step pyrolysis of the MIL‐101 (Fe)@PANI hybrids, unique microstructured carbon tubes with Fe 3 O 4 nanoparticles encapsulated inside the wall were fabricated after the self‐sacrificial template decomposed. The optimized C‐PANI‐MIL‐2 catalyst exhibits a high onset potential of 1.0 V in alkaline media. Out of the negative effect of the disruption of metal‐organic frameworks (MOF) morphology, the ingenious catalytic activities may be ascribed to the well‐defined microtube architecture with a high accessible surface area, the existence of FeN 2+2 /FeN 4 and rich active nitrogen atoms. Moreover, C‐PANI‐MIL‐2 exhibited excellent methanol tolerance and durability compared to a commercial Pt/C catalyst in both electrolytes. This work may provide a new strategy for the design and preparation of microstructured non‐precious metal based catalysts supported on hollow carbon tubes for fuel cells.