Transition-Metal- and Nitrogen-Doped Carbide-Derived Carbon/Carbon Nanotube Composites as Cathode Catalysts for Anion-Exchange Membrane Fuel Cells

Abstract

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.

Bifunctional Oxygen Electrocatalysis on Mixed Metal Phthalocyanine-Modified Carbon Nanotubes Prepared via Pyrolysis

“…M-N-C-type catalysts are promising candidates due to their high ORR electrocatalytic activity, resistance toward corrosion, and high active surface area. 25 , 58 , 59 …”

Bimetal Phthalocyanine‐Modified Carbon Nanotube‐Based Bifunctional Catalysts for Zinc‐Air Batteries

“…[35][36][37][38][39][40][41][42] Thus, one approach to prepare MÀ NÀ C catalysts that contain these specific catalytic active sites is by high-temperature pyrolysis in the presence of transition metal salts (e. g. iron or cobalt acetate) and nitrogen precursor (e. g. 1,10-phenanthroline) along with carbon support materials in inert atmosphere. [16,43,44] Another interesting way to form M-N x centres and metal oxides in carbon matrix is to use MN 4 macrocyclic compounds (e. g. transition metal phthalocyanines or porphyrins) for this purpose. Such as, MÀ NÀ C type catalysts derived from different metal phthalocyanines (MPcs) in the combination of various carbon supports have been prepared and studied towards the ORR, OER and for both, the ORR and OER processes.…”

“…It has previously been observed that incorporation of M‐N x centres and MO x onto conductive carbon support provide remarkable ORR and OER electrocatalysis, respectively [35–42] . Thus, one approach to prepare M−N−C catalysts that contain these specific catalytic active sites is by high‐temperature pyrolysis in the presence of transition metal salts (e. g. iron or cobalt acetate) and nitrogen precursor (e. g. 1,10‐phenanthroline) along with carbon support materials in inert atmosphere [16,43,44] . Another interesting way to form M‐N x centres and metal oxides in carbon matrix is to use MN 4 macrocyclic compounds (e. g. transition metal phthalocyanines or porphyrins) for this purpose.…”

The joint effect of electrical conductivity and surface oxygen functionalities of carbon supports on the oxygen reduction reaction studied over bare supports and Mn–Co spinel/carbon catalysts in alkaline media

“…silver, nickel), and nitrogen co-doped carbons have been investigated and used as the ORR catalysts. [16][17][18][19][20][21][22][23][24] Transition metal oxides (TMOs) of spinel structure are commonly applied as catalysts for the ORR in AEMFCs. Numerous TMOs exhibit satisfactory catalytic activity in the ORR and the oxygen evolution reaction (OER) with the advantages of being inexpensive, naturally abundant, and environmentally benign.…”