Electroreduction of oxygen over iron macrocyclic catalysts for DMFC applications

Abstract

The performance of macrocyclic catalysts in oxygen reduction was investigated for a direct methanol fuel cell. The dependence of catalytic activity on different factors was determined for two classes of precursors; namely, iron porphyrin (Fe-PC) and iron phthalocyanine (Fe-TPP). It was found that there was an optimal heattreating temperature for each precursor. Heat-treated Fe-TPP shows maximum activity at 750°C, while the highest performance in the case of Fe-PC is observed at 500°C. It was shown that oxygen reduction activity is affected by the number of nitrogen bonds formed with iron, particle size, and formation of carbon layers.

Methanol-Tolerant M–N–C Catalysts for Oxygen Reduction Reactions in Acidic Media and Their Application in Direct Methanol Fuel Cells

“…Four years later, Olson and coworkers published a maximum power density of 27 mW cm −2 , with a cobalt-based catalyst at the cathode, at a higher temperature of 70 • C, and methanol concentrations from 0.28 to 4.7 M, with an insignificant variation of voltage-current curves [48]. Almost simultaneously, Serov et al reported DMFC results with a similar power density of 28 mW cm −2 , using an iron-based catalyst at the cathode [45]. The operating temperature in this case was slightly higher, 80 • C, while the methanol concentration was lower (1 M).…”

“…Another class of precursors largely employed for the synthesis of the Fe-N-C or Co-N-C catalysts is based on porphyrins [45][46][47][48][49]. Serov et al [45] synthesized non-PGM catalysts based on M-tetraphenylporphyrin (TPP) (M: Fe, Co, Ni, Cu, Mn, and Zn) and iron phthalocyanine (PC). Kong et al [46] prepared Co-N-C catalysts by mixing etched graphene oxide (GO) sheets with abundant in-plane pores and a porphyrin containing both Co and N elements as the doping precursor.…”

An overview of unsolved deficiencies of direct methanol fuel cell technology: factors and parameters affecting its widespread use

“…On the other hand, CH 3 OH-tolerant catalysts, such as metal phthalocyanines, porphyrins, metal oxides, metal carbides and Ru-based chalcogenides were found to have competitive ORR activity; however, their lifetimes need to be improved [87][88][89][90][91]. Various C-supported binary and ternary alloys of Pt, such as Pt-Co/C, Pt-Cr/C, Pt-Ni/C, Pt-Fe/C and Pt-Cr-Co/C showed better performance compared with Pt/C as cathode catalysts in DMFCs [53,[88][89][90][91][92][93][94][95]. Lee and Popov [96] provided a short review on the catalytic properties of the selected Ru compounds, including crystalline Chevrel-phase chalcogenides, nanostructured Ru and Ru-Se clusters and Ru-N chelate compounds.…”

Study of pyrolyzed hemin/C as non-platinum cathodic catalyst for direct methanol fuel cells

“…Since metallic macrocycle catalysts are inactive for the electrooxidation of small organic molecules [15,16], they are more suitable to be applied in direct alcohol fuel cells.…”

“…Transition metal macrocyclic compounds are methanol-tolerant [15,16]. When methanol crosses from the anode to the cathode, it does not produce a potential drop with a non-platinum catalyst.…”