Modifying Commercial Carbon with Trace Amounts of ZIF to Prepare Derivatives with Superior ORR Activities.

Reducing costs while maintaining high activities and stabilities of oxygen reduction reaction (ORR) catalysts has long been pursued for applications to membrane fuel cells. Here, an absorption-reaction method is used to prepare a zeolitic imidazolate framework coated commercial carbon, and the pyrolysis of such material brings about impressive ORR activities and stabilities with large diffusion-limited current density, half-wave potential, and no obvious decay after 10 000 cyclic voltammetry cycles, which is even better than that of the commercial Pt/C catalysts. The absorption-reaction method is realized by simply soaking the commercial carbon black sequentially in Co(NO3 )2 and 2-methylimidazole solutions at ambient conditions. The detailed analysis on such carbon materials reveals that both Co and N are essential to activities, even the amount of N and Co species is very low. The reduction of raw materials and simplified handling procedures result in well-controlled costs in applications.