Nitrogen-doped carbon nanofiber catalyst for ORR in PEM fuel cell stack: Performance, durability and market application aspects

Abstract

A noble metal-free catalyst based on N-doped carbon nanofibers supported on graphite (N-CNF 1 ) was employed for the oxygen reduction at the cathode of a Nafion PEMFC with a commercial Pt/C anode. Obtained performance in pure H2 and O2 indicated the presence of significant mass-transport limitations when utilizing catalyst loadings between 1 and 10 mg cm -2 . Strategies to reduce the limitations were explored by optimization of the cathode ionomer content, catalyst loading and application technique. Pore-formers (Li2CO3, (NH4)2CO3 and polystyrene microspheres) were utilized to improve the mass-transport within the layer. A maximum of 72 mW cm -2 and 1400 A g -1 or 300 W g -1 at peak power was demonstrated. The catalyst was then applied to the cathode of a 10-cell fuel cell stack, and a 400-hour durability test was conducted. The average cell voltage decay amounted to 162 µV h -1 . Finally, a market application analysis was conducted by comparing the capital and operating costs of FC systems based on Pt/C and on N-CNF cathodes. While the cheap (3,32 € g -1 ) N-CNF catalyst reduces the single MEA cost by almost a third, the total cost of ownership of an N-CNF based PEMFC system is still higher due to lower cell performance.

Carbon Nanofibers as Potential Catalyst Support for Fuel Cell Cathodes: A Review

“…Among the three, higher performance was achieved with (NH 4 )CO 3 . 235 The power density obtained was found to be 300 W g −1 , with a catalyst loading of 0.243 mg cm −2 in H 2 /O 2 , and with 2.6 bar back pressure. The durability was performed at 20 mA cm −2 for 400 h. The degradation rate of the fuel cell stack was found to be 162 μV h −1 with 17% loss in the power density.…”

“…The pore-forming agents utilized are polystyrene microspheres, Li 2 CO 3 , and (NH 4 )­CO 3 . Among the three, higher performance was achieved with (NH 4 )­CO 3 . The power density obtained was found to be 300 W g –1 , with a catalyst loading of 0.243 mg cm –2 in H 2 /O 2 , and with 2.6 bar back pressure.…”

Evaluation of ORR active sites in nitrogen-doped carbon nanofibers by KOH post treatment

“…Developing novel, highly active, and cheap catalysts for the oxygen reduction reaction (ORR) in acidic electrolyte is crucial to take the PEM fuel cell technology to market [1][2][3][4]. In this objective, several new catalytic materials have recently been developed through rational design, and shown promising catalytic performance for the oxygen reduction [4][5][6].…”

“…One of the most promising materials is nitrogen doped carbon nanomaterials prepared in the presence of Fe, hereafter called Fe-N-C, which have opened a new opportunity to replace the costly Ptbased catalysts currently used [7][8][9][10][11][12][13]. However, a PEM fuel cell assembled with state-of-theart Fe-N-C catalysts generate lower current density than the state-of-the-art Pt-based catalysts [2]. In turn, this increases the capital cost for the Fe-N-C fuel cell stack as the required electrode area increases, thereby increasing the requirements of other fuel cell components such as the bipolar plates.…”

Proton Exchange Membrane Fuel Cells: Thermodynamics, Components and Applications

“…Metal bazlı olmayan katalizör çalışmalarında ise en dikkat çeken azot katkılı karbon nanofiber (N-CNT) katalizörlerdir. Üretilen bu katalizörler performans ve kararlılık olarak Pt katalizörü geçemese de maliyet açısından umut vaat etmektedir[28]. İstenilen şartları sağlayabilecek yeni bir katalizör üretmek için diğer yaklaşım ise; platin bazlı kompozit katalizörler (Pt 3 Co, Pt-Pd, Pt/V-TiO…”