Activation of Various Fe‐Based Precursors on Carbon Black and Graphite Supports to Obtain Catalysts for the Reduction of Oxygen in Fuel Cells

Abstract

Three synthetic paths have been used to prepare iron-based catalysts for the electrochemical reduction of oxygen in solid polymer fuel cells. The catalyst precursor used in the first synthetic path was a dispersion of Fe(OH)2 on carbon black (Vulcan) that was reduced at 600°C in H2. The second synthetic path involved a method to intercalate FeC13 that was first used with graphite and then extended to Vulcan. The oxidized iron was reduced by either heating the resulting materials at 600°C in 112 or by reacting them at room temperature with K-naphthalene in a nonaqueous solution. In the third synthetic path, Fe particles were generated directly on Vulcan by the reduction in a nonaqueous solution of FeC12 with triethylborohydride. All these iron containing materials were then activated at 1000°C in the presence of acetonitrile in order to transform them into active catalysts for °2 reduction. The best catalyst was obtained by extending the intercalation method of FeC13 to carbon black (Vulcan) and then reducing the oxidized iron with K-naphthalene. Based on electrochemical and physicochemical analysis (mostly scanning electron microscopy and x-ray diffraction analysis) it is suggested that iron is included or intercalated in the carbon black particles. The higher catalytic activity of this material compared to the others is explained by the progressive release of the iron from the carbon black particles and its reaction with acetonitrile during the final thermal activation step at 1000°C.

Heteroatom-Doped Carbon Nanostructures as Oxygen Reduction Reaction Catalysts in Acidic Media: An Overview

“…Van Veen et al were one of the earlier groups to report the formation of a new catalytic site upon high temperature treatments of carbon-supported organo-metallic macrocycles [8]. Later studies have reported that it was not necessary to begin with organic macrocycles in order to produce active and stable nonnoble metal ORR electrocatalysts [9]. Often heating an N and C source over metal particles was sufficient.…”

A non-noble material cathode catalyst dual-doped with sulfur and nitrogen as efficient electrocatalysts for oxygen reduction reaction

“…Regarding both the catalytic activity and stability of pyrolyzed M-N/C catalysts, there is a general agreement in the literature that four factors are necessary in achieving an active and stable non-Pt metal ORR catalyst: transition metal, nitrogen coordinators on these catalysts, source carbon support and pyrolysis [15]. As established by Dodelet and co-workers [15][16][17] and now widely confirmed by experiments, nitrogen is a necessary component of the catalyst site in order to form an active catalyst. This is why several different types of nitrogen-containing compounds have been employed as the precusors to form M-N/C complexes.…”

Advances in Carbon‐Incorporated Non‐Noble Transition Metal Catalysts for Oxygen Reduction Reaction in Polymer Electrolyte Fuel Cells

“…11 Table 1 summarized the preparation parameters and the corresponding ORR activities of NNMCs reported in the past two years. [14][15][16][17][18][19][20][21][22][23][24][25][26] Also, nitrogen is a necessary component of the catalyst site to form an active catalyst as es-tablished by Fournier et al 27 and widely confirmed by experiments. Hence, we only collect the literatures regarding the addition of nitrogen-containing precursor to the synthetic reactions during preparation.…”