Non-precious metal cathodes for anion exchange membrane fuel cells from ball-milled iron and nitrogen doped carbide-derived carbons

Abstract

Iron and nitrogen doping of carbon materials is one of the promising pathways towards replacing Pt/C in polymer electrolyte fuel cell cathodes. Here, we show a synthesis method to produce highly active non-precious metal catalysts and study the effect of synthesis parameters on the oxygen reduction reaction (ORR) activity in high-pH conditions. The electrocatalysts are prepared by functionalizing silicon carbide-derived carbon (SiCDC) with 1,10-phenanthroline, iron(II)acetate and, optionally polyvinylpyrrolidone, by ball-milling with ZrO2 in dry or wet conditions, followed by pyrolysis at 800 °C. The catalysts are characterized by scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, N2 physisorption and inductively coupled plasma mass spectrometry. By optimizing the ball-milling conditions, we achieved a reduction in the size of SiCDC grains from >1 µm to 200 nm without negatively affecting the

FeNC Electrocatalysts with Densely Accessible FeN4 Sites for Efficient Oxygen Reduction Reaction

“…[ 11 ] The WT spectrum of FeNC/MA only revealed one contour intensity maximum at ≈ 4.50 Å −1 at k space which was similar to that of FePc, implying again the FeN first shell coordination (Figure 2c). [ 23,48 ] The WT EXAFS analysis indicated that the Fe atoms existed as mononuclear centers without the presence of Fe‐derived crystalline structures. EXAFS fitting analysis gave the coordination number and bonding distance of the central Fe atoms with respect to the neighboring scattering atoms in FeNC/MA, providing a first shell FeN coordination number and bonding distance of 4.5 ± 0.2 and 1.5 ± 0.2 (Å), respectively (Figure 2b and Table S6, Supporting Information).…”

Iron and cobalt containing electrospun carbon nanofibre-based cathode catalysts for anion exchange membrane fuel cell

“…5b). The micropores are considered necessary to reach high density of M-Nx sites [45,46], while the mesopores can promote faster mass transfer [6,16]. The presence of high number of ORR-active sites was also supported by Raman spectroscopy, which showed a very defective carbon structure indicated by the bonding of different species through sp 3 carbon.…”

Boosting activity toward oxygen reduction reaction of a mesoporous FeCuNC catalyst via heteroatom doping-induced electronic state modulation

“…22 Besides, the understanding of the AEMFC system has been improved via various efforts devoted toward facilitating advancements in the eld of component design, including catalysts and ionomers, and operating conditions of the AEMFC. [23][24][25][26][27][28] As MNC catalysts feature transition metals bonded to several nitrogen atoms (M-N x ) as the active sites for oxygen reduction, many studies have focused on the generation of M-N x moieties and controlling their electronic states to enhance catalytic activity. [29][30][31] Reactions promoted by carbon-based electrocatalysts can be accelerated by breaking the charge neutrality of the carbon matrix, e.g., via the introduction of electronwithdrawing or -donating elements.…”