The effect of temperature on ionic liquid modified Fe-N-C catalysts for alkaline oxygen reduction reaction

Wolker, Thomas; Brunnengräber, Kai; Martinaiou, Ioanna; Lorenz, Nick; Zhang, Guirong; Kramm, Ulrike I.; Etzold, Bastian J. M.

doi:10.1016/j.jechem.2021.11.042

Cited by 18 publications

(8 citation statements)

References 42 publications

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“…Similarly, Duclaux et al studied the adsorption of ILs on carbon materials and also found that several imidazolium-based ILs would be preferentially adsorbed in the micropores instead of the mesopores of activated carbons . Previously, we found that IL ([MTBD][NTf 2 ]) would first fill the micropores of carbon-supported Pt nanoparticles and Fe–N–C ORR catalysts based on comprehensive N 2 -sorption analyses. ,, This phenomenon is not surprising when considering the inversely proportional relationship between the pore radius and the capillary pressure, , which acts as the main driving force for the liquid to fill the pores.…”

Section: Resultsmentioning

confidence: 56%

“…In contrast, ZDC–IL possesses a much smaller surface area (134 m 2 g –1 ) and total pore volume (0.34 mL g –1 ) due to the pore filling by the IL phase. As shown in Figure a, the nitrogen sorption isotherms of both ZDC and ZDC–IL can be identified as a hybrid type of I(b)–II with a type H3 hysteresis, which is analogous to other porous carbon materials with wide pore size distributions (PSD). − It is notable that the N 2 uptake in the micropore region (low relative pressure region) is significantly reduced, as shown in the isotherm curves. Specifically, the micropore volume of ZDC is decreased from 0.24 to 0.04 mL g –1 , which corresponds to 74% of the reduction in the total pore volume, implying that the IL would first fill the micropores of ZDC.…”

Section: Resultsmentioning

confidence: 86%

“…30 Previously, we found that IL ([MTBD]-[NTf 2 ]) would first fill the micropores of carbon-supported Pt nanoparticles and Fe−N−C ORR catalysts based on comprehensive N 2 -sorption analyses. 28,31,32 This phenomenon is not surprising when considering the inversely proportional relationship between the pore radius and the capillary pressure, 33,34 which acts as the main driving force for the liquid to fill the pores.…”

Section: Structural and Morphological Characterizationsmentioning

confidence: 96%

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Increasing Accessible Active Site Density of Non-Precious Metal Oxygen Reduction Reaction Catalysts through Ionic Liquid Modification

Zhang

Yong

Shen

et al. 2023

ACS Appl. Mater. Interfaces

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Non-precious metal catalysts show great promise to replace the state-of-the-art Pt-based catalysts for catalyzing the oxygen reduction reaction (ORR), while their catalytic activity still needs to be greatly improved before their broad-based application. Here, we report a facile approach to improving the performance of zeolitic imidazolate framework-derived carbon (ZDC) toward the ORR by incorporating a small amount of ionic liquid (IL). The IL would preferentially fill the micropores of ZDC and greatly enhance the utilization of the active sites within the micropores, which are initially not accessible due to insufficient surface wetting. It is also disclosed that the ORR activity in terms of kinetic current at 0.85 V depends on the loading amount of the IL, and the maximum activity is obtained at a mass ratio of IL to ZDC at 1.2. The optimum stems from the counterbalance between the enhanced utilization of the active sites within the micropores and the retarded diffusion of the reactants within the IL phase due to its high viscosity.

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Section: Resultsmentioning

confidence: 56%

Section: Resultsmentioning

confidence: 86%

Section: Structural and Morphological Characterizationsmentioning

confidence: 96%

See 1 more Smart Citation

Increasing Accessible Active Site Density of Non-Precious Metal Oxygen Reduction Reaction Catalysts through Ionic Liquid Modification

Zhang

Yong

Shen

et al. 2023

ACS Appl. Mater. Interfaces

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“…In addition, recently, a novel approach based on the use of ionic liquid (IL) such as [BMIM][NTf 2 ], [MTDB][BETI], [DEMA][TfO], etc. to engineer the electrochemical triple-point interface (catalyst–electrolyte–reactant) of both PGM and non-PGM-based catalysts has emerged as a promising alternative under the umbrella of “Solid Catalyst with Ionic Liquid Layer (SCILL)” to boost ORR activity in acidic and alkaline media. − The implementation of this approach is to modify the electrocatalysts by coating their inner surface with a controlled amount of ILs, which have attracted special attention in electrochemistry owing to their high ionic conductivity, broad electrochemical window, and good chemical stability . Furthermore, the ILs with fluorinated side chains of the anionic parts are also hydrophobic in nature in addition to having higher O 2 solubility due to the strong affinity of fluorines for oxygen, two desirable properties in ORR electrocatalysts .…”

Section: Introductionmentioning

confidence: 99%

Design and Performance Enhancement of Cobalt-Encapsulated Nitrogen-Doped Carbon Nanofiber Electrocatalyst through Ionic Liquid Modification for Efficient Oxygen Reduction

Parida

Ganguly

Barik

et al. 2023

ACS Appl. Nano Mater.

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The design of platinum-group-metal-free (PGM-free) electrocatalysts with appreciable activity and durability toward the oxygen reduction reaction (ORR) in acidic environments is a big challenge. Here, we report an efficient oxygen reduction activity of a Co-encapsulated nitrogen-doped carbon with nanofiber networks and its ionic liquid-modified interface in an acidic medium. The robust structure of the nanofibers embedded on a rigid framework derived from a zeolitic imidazole framework (ZIF-67) delivers promising activity and durability to the catalyst comparable to the state-of-the-art Pt/C. The ionic-liquid-modified catalyst shows a half-wave potential of 0.71 V vs RHE in oxygen-saturated 0.5 M H2SO4 along with activity reduction by only 11 mV (E 1/2) after 5000 cycles of the accelerated durability test. The catalyst also retains 71% of its original current during the short-term durability test. Furthermore, the electron transfer number and H2O2 yield of the catalyst during the ORR approaches 3.88–3.90 and 5.9–4.8% in the potential range 0.4–0.7 V vs RHE. The ORR performance of the ionic-liquid-modified catalyst is superior among all ionic liquid-based non-PGM catalysts reported so far in acidic media.

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“…The anion-exchange membrane fuel cell (AEMFC) technology enables the conversion of chemical energy stored in hydrogen into electric energy with no emissions other than pure water. AEMFCs offer the possibility to use platinum group metal (PGM)-free catalysts for both reactions, the hydrogen oxidation reaction (HOR) [1][2][3][4] and the oxygen reduction reaction (ORR) [5][6][7][8][9][10]. Recent comprehensive reviews and studies further highlight the HOR challenges in alkaline pH [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Role of Fe in the hydrogen oxidation reaction in a NiFe-based catalyst: an in situ Mössbauer spectroscopic investigation

Davydova

Singh

et al. 2023

J. Phys. Energy

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Nickel-based catalysts reach a high activity for the hydrogen oxidation reaction (HOR) in anion exchange membrane fuel cells. While incorporation of iron significantly decreases the HOR overpotential on NiFe-based catalysts, the reason for the enhanced activity remains only partially understood. For the first time, in situ 57Fe Mössbauer spectroscopy is used to gain insights into the iron-related composition at different potentials. The aim is to evaluate which changes occur on iron at potentials relevant for the HOR on the active Ni sites. It is found that different pre-conditionings at low potentials stabilize the iron at a low oxidation state as compared to the as-prepared catalyst powder. It is likely that the lower average oxidation state enables a higher exchange current density and a more efficient OH adsorption, which make the Volmer step much faster in the HOR. Insights from in situ Mössbauer spectroscopy enlighten the role of iron in the nickel-iron catalyst, paving the way for developing improved Ni-based catalysts for HOR catalysis.

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The effect of temperature on ionic liquid modified Fe-N-C catalysts for alkaline oxygen reduction reaction

Cited by 18 publications

References 42 publications

Increasing Accessible Active Site Density of Non-Precious Metal Oxygen Reduction Reaction Catalysts through Ionic Liquid Modification

Increasing Accessible Active Site Density of Non-Precious Metal Oxygen Reduction Reaction Catalysts through Ionic Liquid Modification

Design and Performance Enhancement of Cobalt-Encapsulated Nitrogen-Doped Carbon Nanofiber Electrocatalyst through Ionic Liquid Modification for Efficient Oxygen Reduction

Role of Fe in the hydrogen oxidation reaction in a NiFe-based catalyst: an in situ Mössbauer spectroscopic investigation

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