Transition-metal- and nitrogen-codoped carbide-derived carbon/carbon nanotube composites (M-N-CDC/CNT) have been prepared, characterized, and used as cathode catalysts in anion-exchange membrane fuel cells (AEMFCs). As transition metals, cobalt, iron, and a combination of both have been investigated. Metal and nitrogen are doped through a simple high-temperature pyrolysis technique with 1,10-phenanthroline as the N precursor. The physicochemical characterization shows the success of metal and nitrogen doping as well as very similar morphologies and textural properties of all three composite materials. The initial assessment of the oxygen reduction reaction (ORR) activity, employing the rotating ring–disk electrode method, indicates that the M-N-CDC/CNT catalysts exhibit a very good electrocatalytic performance in alkaline media. We find that the formation of HO 2 – species in the ORR catalysts depends on the specific metal composition (Co, Fe, or CoFe). All three materials show excellent stability with a negligible decline in their performance after 10000 consecutive potential cycles. The very good performance of the M-N-CDC/CNT catalyst materials is attributed to the presence of M-N x and pyridinic-N moieties as well as both micro- and mesoporous structures. Finally, the catalysts exhibit excellent performance in in situ tests in H 2 /O 2 AEMFCs, with the CoFe-N-CDC/CNT reaching a current density close to 500 mA cm –2 at 0.75 V and a peak power density ( P max ) exceeding 1 W cm –2 . Additional tests show that P max reaches 0.8 W cm –2 in an H 2 /CO 2 -free air system and that the CoFe-N-CDC/CNT material exhibits good stability under both AEMFC operating conditions.

Cobalt- and nitrogen-doped carbide-derived carbon/carbon nanotube (CDC/CNT) composites are prepared and used as oxygen reduction reaction (ORR) electrocatalysts for an anion exchange membrane fuel cell (AEMFC) cathode. For the doping, high-temperature pyrolysis is applied using a cobalt salt and a nitrogen precursor (either dicyandiamide, urea, or melamine). During the doping, (i) new mesopores are formed as confirmed by the N2 physisorption results, (ii) atomically dispersed cobalt is present on the catalysts as detected by scanning transmission electron microscopy, and (iii) N-pyridinic and Co–N4 are the dominant N-containing species as shown by X-ray photoelectron spectroscopy. This indicates that using the composite of CDC and CNTs as well as the cobalt salt and nitrogen precursor is advantageous for the preparation of electrocatalysts. All three catalyst materials demonstrate similarly good electrocatalytic activity toward O2 electroreduction in alkaline medium and excellent stability after 10000 repetitive potential cycles. The Co-N-CDC/CNT catalyst as the cathode material together with a hexamethyl-p-terphenyl poly­(benzimidazolium) (HMT-PMBI) membrane exhibits excellent AEMFC performance by reaching maximum power density of 577 mW cm–2.

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