Activity, Performance, and Durability for the Reduction of Oxygen in PEM Fuel Cells, of Fe/N/C Electrocatalysts Obtained from the Pyrolysis of Metal-Organic-Framework and Iron Porphyrin Precursors

Yang, Lijun; Larouche, Nicholas; Chenitz, Régis; Zhang, Gaixia; Lefèvre, Michel; Dodelet, Jean‐Pol

doi:10.1016/j.electacta.2015.01.201

Cited by 130 publications

(101 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This result surpasses by a factor of two the current density at 0.5 V previously obtained with Basolite ® and with our typical process parameters (400 rpm, flash pyrolysis in Ar, Figure 8A) [46]. The initial peak power density of 500 mW cm −2 is among the highest reported for Fe-N-C catalysts, including those pyrolyzed in NH3 [8][9][10]12,26,27,30,47]. This is particularly interesting since such Fe-N-C catalysts pyrolyzed in inert gas are intrinsically more stable than NH3-pyrolyzed Fe-N-C catalysts [8].…”

Section: Characterization Of Fe-n-c Catalysts Templated From Various mentioning

confidence: 71%

“…halved power performance after 50 h of operation, characteristic for NH3-pyrolyzed catalysts [8,10,28]. In contrast, Fe-N-C catalysts derived from Fe(II), 1,10-phenanthroline and ZIF-8 but pyrolyzed in Argon are initially less active but more stable [8,29,30]. Other Fe-and Fe-Co-N-C catalysts pyrolyzed in inert atmosphere have resulted in a constant current density at 0.4-0.5 V over several hundred hours of operation in PEMFC, a promising achievement toward more durable Me-N-C catalysts [9,31].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of ZIF-8 Crystal Size on the O2 Electro-Reduction Performance of Pyrolyzed Fe–N–C Catalysts

2015

View full text Add to dashboard Cite

Abstract:The effect of ZIF-8 crystal size on the morphology and performance of Fe-N-C catalysts synthesized via the pyrolysis of a ferrous salt, phenanthroline and the metal-organic framework ZIF-8 is investigated in detail. Various ZIF-8 samples with average crystal size ranging from 100 to 1600 nm were prepared. The process parameters allowing a templating effect after argon pyrolysis were investigated. It is shown that the milling speed, used to prepare catalyst precursors, and the heating mode, used for pyrolysis, are critical factors for templating nano-ZIFs into nano-sized Fe-N-C particles with open porosity. Templating could be achieved when combining a reduced milling speed with a ramped heating mode. For templated Fe-N-C materials, the performance and activity improved with decreased ZIF-8 crystal size. With the Fe-N-C catalyst templated from the smallest ZIF-8 crystals, the current densities in H2/O2 polymer electrolyte fuel cell at 0.5 V reached ca. 900 mA cm −2 , compared to only ca. 450 mA cm −2 with our previous approach. This templating process opens the path to a morphological control of Fe-N-C catalysts derived from metal-organic frameworks which, when combined with the versatility of the coordination chemistry of such materials, offers a platform for the rational design of optimized Metal-N-C catalysts.

show abstract

Section: Characterization Of Fe-n-c Catalysts Templated From Various mentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Effect of ZIF-8 Crystal Size on the O2 Electro-Reduction Performance of Pyrolyzed Fe–N–C Catalysts

2015

View full text Add to dashboard Cite

show abstract

“…They exhibit an improved tolerance to the harsh environments present at the cathode of low-temperature FCs; "Ptfree" ECs are approaching an acceptable level of performance and durability at low costs. [38][39][40] In summary, results point out that: a) the best protocol for the preparation of CN-based ECs consists of the pyrolysis of Z-IOPE precursors. In this case, N is introduced in the CN matrix by the transition metal complexes, thus forming "coordination nests" for alloy NPs; b) the concentration of nitrogen influences:…”

Section: Fig 1 (A) Schematic Representation Of Hio-pn and Z-iope Prmentioning

confidence: 99%

Origins, Developments, and Perspectives of Carbon Nitride-Based Electrocatalysts for Application in Low-Temperature FCs

et al. 2015

View full text Add to dashboard Cite

F uel cells (FCs) operating at low temperatures (T < 200 °C)show several very attractive features, including: (a) relatively simple assembly; (b) good compatibility with the environment; and (c) very high efficiency with respect to internal combustion engines. However, the full potential of low-temperature FCs can only be achieved by addressing a number of crucial issues involved in their operation. One of the most important bottlenecks is represented by the slow kinetics of the oxygen reduction reaction (ORR).1 Typical examples of low-temperature fuel cells include proton exchange membrane fuel cells (PEMFCs) and anion-exchange membrane fuel cells (AEMFCs).1 To achieve energy conversion efficiencies and power densities compatible with applications, all these devices require suitable ORR electrocatalysts (ECs) to minimize cathode polarization losses.Ideally, ORR ECs should possess the following features: a) Active sites capable of the highest turnover frequency at the lowest overpotentials; b) A large active surface area, maximizing the number of active sites; c) A morphology that facilitates the efficient transport of reactants and products to and from the active sites; d) High electron conductivity, to minimize ohmic losses; e) A high dielectric environment to aid the ion exchange processes between the active sites and the ion-conducting membrane; f) High stability under operating conditions, to achieve high durability.To comply with these requirements, state-of-the-art ORR ECs consist of Pt-nanocrystals supported on conductive carbon nanoparticles (NPs) that possess a spherical morphology and a large surface area 2 (indicated as "Pt/C ref. ECs"). These systems are characterized by a high dispersion of the ORR active sites, which are easily accessible by the reactants. Their performance is comparable to that of pristine "Pt-black" ECs, but with a reduced loading of precious metal. However, the large-scale rollout of FC technology employing Pt/C ref. ECs is hindered by their insufficient durability and very high costs."Carbon nitride-based electrocatalysts" (CN-based ECs) have shown great promise to address the issues outlined above. CN-based ECs are composed of a carbon-based matrix embedding nitrogen atoms. The matrix coordinates metal-based species, including: (a) NPs of metals (e.g., Pt, Pd), metal alloys (e.g., PtNi x , PdCo y Ni z ), oxides (e.g., Fe 3 O 4 ) or carbides (e.g., FeC x ); or (b) coordination complexes of single metal atoms (e.g., Fe, Co).3 There are two main driving forces behind the development of CN-based ECs. CN-based ECs including Pt-group elements (PGMs) show very high ORR activity and a remarkable tolerance towards the oxidizing conditions typical at the cathodes of low-temperature FCs. 4 The carbon nitride (CN) matrix embeds the various inorganic NPs in "nitrogen coordination nests". 5These strong interactions inhibit the main mechanisms involved in the long-term degradation of typical Pt/C ref. ECs, especially particle agglomeration and particle detachment from the support.

show abstract

“…Based on this phenomenon, four possible reasons are suggested for the decay (schematic illuminated in Fig. 15a) [150,152] [155], decreasing surface basicity and is responsible for initial activity losses; (3) active sites are flooded as oxidized carbon change hydrophobic surfaces into hydrophilic surfaces [149,156]; (4) free radical species attack carbon matrixes [150,157], causing Fenton reagents to form during ORR with Fe existence, leading to corrosion of catalyst and membrane.…”

Section: Decay Of Catalytic Activitymentioning

confidence: 99%

Rational Design and Synthesis of Low-Temperature Fuel Cell Electrocatalysts

Tian

Yang

et al. 2018

Electrochem. Energ. Rev.

View full text Add to dashboard Cite

Recent progresses in proton exchange membrane fuel cell electrocatalysts are reviewed in this article in terms of cathodic and anodic reactions with a focus on rational design. These designs are based around gaining active sites using model surface studies and include high-index faceted Pt and Pt-alloy nanocrystals for anodic electrooxidation reactions as well as Pt-based alloy/core-shell structures and carbon-based non-precious metal catalysts for cathodic oxygen reduction reactions (ORR). High-index nanocrystals, alloy nanoparticles, and support effects are highlighted for anodic catalysts, and current developments in ORR electrocatalysts with novel structures and different compositions are emphasized for cathodic catalysts. Active site structures, catalytic performances, and stability in fuel cells are also reviewed for carbon-based non-precious metal catalysts. In addition, further developmental perspectives and the current status of advanced fuel cell electrocatalysts are provided.

show abstract

Activity, Performance, and Durability for the Reduction of Oxygen in PEM Fuel Cells, of Fe/N/C Electrocatalysts Obtained from the Pyrolysis of Metal-Organic-Framework and Iron Porphyrin Precursors

Cited by 130 publications

References 55 publications

Effect of ZIF-8 Crystal Size on the O2 Electro-Reduction Performance of Pyrolyzed Fe–N–C Catalysts

Effect of ZIF-8 Crystal Size on the O2 Electro-Reduction Performance of Pyrolyzed Fe–N–C Catalysts

Origins, Developments, and Perspectives of Carbon Nitride-Based Electrocatalysts for Application in Low-Temperature FCs

Rational Design and Synthesis of Low-Temperature Fuel Cell Electrocatalysts

Contact Info

Product

Resources

About