The Role of Polyaniline Molecular Structure in Producing High‐Performance Fe‐N‐C Catalysts for Oxygen Reduction Reaction

He, Qian; Chen, Xiuhong; Jia, Fengqiu; Ding, Wei; Zhou, Yuanyuan; Wang, Jian; Song, Xiaoyun; Jiang, Jinxia; Liu, Qiang; Li, Jing; Wei, Zidong

doi:10.1002/slct.201901329

Cited by 9 publications

(9 citation statements)

References 34 publications

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“…900 °C was reported to give excellent performance . The content of quinoid rings in PANI molecular structure is also an influential factor . On the other hand, the current density is correlated with density of accessible active sites .…”

Section: Methodsmentioning

confidence: 99%

Pyrolysis of Iron‐Containing Polyanilines under Micropore Generation Control: Electrocatalytic Performance in the Oxygen Reduction Reaction

et al. 2020

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Pyrolyzed iron-containing polyaniline (CÀ Fe-PANI) is one of the most promising candidates as a non-precious metal based electrocatalyst for oxygen reduction reaction (ORR). Although the ORR activity depends on the surface area arisen from pyrolysis-generated micropores on CÀ Fe-PANI particles, the micropore generation is hindered by pyrolysis-formed iron nanoparticles (Fe NPs) embedded inside CÀ Fe-PANI particles. Here, we demonstrate the pyrolysis of iron-containing PANIs under suppression of micropore-generation hindrance by blocking the Fe NPs formation. The higher-molecular-weight (MW: 100,000) PANI was dispersed in an FeCl 3 solution before pyrolysis for preventing FeCl 3 penetration inside PANI particles. As a result, as compared to the case of lower-MW (5,000) PANI, the Fe NPs formation was more suppressed inside catalyst particles to give 1.9 (1.8) times micropore volume (specific surface area), leading to a 11 % higher current density in ORR electrocatalytic performance test in acidic media. Polymer electrolyte fuel cells (PEFCs) attract considerable attentions as potential power sources for both stationary and mobile applications. [1] To increase energy conversion efficiency, Pt-based materials are currently employed as the catalysts for both hydrogen oxidation reactions (HORs) at the anode and oxygen reduction reactions (ORRs) at the cathode. [1c] However, due to kinetically sluggish ORRs, as compared to HOR, a relatively large amount of Pt would need to be used at the cathode, making PEFCs too expensive to be applied as practical power sources. For the widespread application of PEFCs, therefore, a low-cost ORR catalyst with high performance must be developed. From such a view point, low-Pt or non-precious metal based electrocatalysts have been developed for ORR. Among them, non-precious metal based catalysts attract attentions because of their low cost. This seems to evolve from the report on ORR catalytic activity of Cophthalocyanine, [2] one of the N 4-chelate complexes. After that, the stability of N 4-chelates in acidic media was enhanced through the thermal pretreatment on carbon supports. [3] Since then, a huge number of researchers have reported a wide variety of analogous carbonaceous materials containing heteroatoms (e. g. N, B, P, S) and/or transition metal species (e. g. Fe, Co, Cu, Mn, Ni) with or without carbon supports. [4] On the other hand, polyaniline (PANI) is well known as one of the conducting polymers possessing the redox properties. Thus far, we have reported complexation of PANI with various transition metals [5] and catalytic reactions [6] mediated by the complexes. In this case, d-π conjugated systems are considered to be formed. Meanwhile, PANI is one of the most promising candidates as a precursor for ORR electrocatalysts. The pyrolyzed products of such complexes or mixtures comprising transition metals and PANIs

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Section: Methodsmentioning

confidence: 99%

Pyrolysis of Iron‐Containing Polyanilines under Micropore Generation Control: Electrocatalytic Performance in the Oxygen Reduction Reaction

et al. 2020

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“…Later on, they systematically investigated the effects of pyrolysis conditions, metal salts, and carbon supports on the catalyst morphologies and performances [86]. Wei's group [87] also investigated the relationship between the molecular structure of polyaniline and the performance of derived Fe@NC catalysts. The morphology of the polyaniline was controlled by the molar ratios of ammonium persulfate to aniline monomers.…”

Section: N-containing Conductive Polymer Assisted Strategymentioning

confidence: 99%

Advanced transition metal/nitrogen/carbon-based electrocatalysts for fuel cell applications

et al. 2020

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The development of advanced transition metal/nitrogen/carbon-based (M/N/C) catalysts with high activity and extended durability for oxygen reduction reaction (ORR) is critical for platinum-group-metal (PGM) free fuel cells but still remains great challenging. In this review, we summarize the recent progress in two typical M/N/C catalysts (atomically dispersed metalnitrogen-carbon (M-N-C) catalysts and carbon-supported metal nanoparticles with N-doped carbon shells (M@NC)) with an emphasis on their potential applications in fuel cells. Starting with understanding the active sites in these two types of catalysts, the representative innovative strategies for enhancing their intrinsic activity and increasing the density of these sites are systematically introduced. The synergistic effects of M-N-C and M@NC are subsequently discussed for those M/N/C catalysts combining both of them. To translate the material-level catalyst performance into high-performance devices, we also include the recent progress in engineering the porous structure and durability of M/N/C catalysts towards efficient performance in fuel cell devices. From the viewpoint of industrial applications, the scale-up cost-effective synthesis of M/N/C catalysts has been lastly briefed. With this knowledge, the challenges and perspectives in designing advanced M/N/C catalysts for potential PGM-free fuel cells are proposed.

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“…In fact, the morphology of the polymer‐derived Fe–N–C can be tuned by controlling the nanostructure of PANI through the manipulation of the PANI molecular structure 17 . For instance, He et al manipulated the PANI molecular structure during the synthesis of Fe–N–C by adjusting the ratio of oxidizing agent to aniline, resulting in different quinoid ring (QR) contents 18 . This is because the higher the degree of oxidation is, the higher the QR content produced.…”

Section: Introductionmentioning

confidence: 99%

Influence of Fe–N–C morphologies on the oxygen reduction reaction in acidic and alkaline media

Junaidi

Tan

Wong

et al. 2023

Asia-Pacific J Chem Eng

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The development of nonnoble metal oxygen reduction reaction (ORR) catalysts for fuel cells has been motivated by the high cost and limited supply of noble metals, as well as the desire to improve the performance and durability of this type of energy conversion device. In this study, nonnoble Fe–N–C catalyst was synthesized using a zeolitic imidazole framework (ZIF‐8), poly (aniline), and 10,10′‐dibromo‐9,9′‐bianthry as precursors to produce Fe–N–C with hollow sphere (HS), amorphous bulky structure (B), and sheet‐like thin sheet (N) structure. The Fe–N–C catalyst was analysed in terms of their shape, crystal structure, pore characteristics, and elemental composition. Among all the Fe–N–C catalysts, Fe–N–C_HS had the highest total surface area, followed by Fe–N–C_B and Fe–N–C_N. To evaluate their ORR catalytic activity, a half‐cell electrochemical experiment with .1 M KOH and .1 M HClO4 as the alkaline and acidic electrolytes was conducted. This study revealed that Fe–N–C_HS exhibited the highest onset potential but the Fe–N–C_B has the highest limiting current density in alkaline medium; meanwhile, in acidic media, Fe–N–C_HS shows the best ORR performance with the highest onset potential and limiting current. This highly porous Fe–N–C_HS catalyst also demonstrated active site activation and excellent stability compared with the other samples as well as commercial Pt/C in acidic electrolyte, which suggests its potential for application in proton exchange membrane fuel cells (PEMFCs).

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The Role of Polyaniline Molecular Structure in Producing High‐Performance Fe‐N‐C Catalysts for Oxygen Reduction Reaction

Cited by 9 publications

References 34 publications

Pyrolysis of Iron‐Containing Polyanilines under Micropore Generation Control: Electrocatalytic Performance in the Oxygen Reduction Reaction

Pyrolysis of Iron‐Containing Polyanilines under Micropore Generation Control: Electrocatalytic Performance in the Oxygen Reduction Reaction

Advanced transition metal/nitrogen/carbon-based electrocatalysts for fuel cell applications

Influence of Fe–N–C morphologies on the oxygen reduction reaction in acidic and alkaline media

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