Optimized Enhancement Effect of Sulfur in Fe–N–S Codoped Carbon Nanosheets for Efficient Oxygen Reduction Reaction

Ni, Baoxia; Chen, Rui; Wu, Luming; Xu, Xueyan; Shi, Chengxiang; Sun, Pingchuan; Chen, Tiehong

doi:10.1021/acsami.0c05095

Cited by 54 publications

(52 citation statements)

References 52 publications

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“…The LSV curves of Fe−N−C/700 with different rotation rates are shown in Figure 3d. The corresponding K−L plots (inset in Figure 3d) exhibited a perfect linearity over the potential range of 0.4‐0.6 V, suggesting first‐order reaction kinetics to oxygen concentration and similar electron‐transfer numbers for ORR at different electrode potentials [45–47] . In addition, RRDE measurements were carried out to acquire a more accurate electron‐transfer number as well as the yield of H 2 O 2 (Figure 3e).…”

Section: Resultsmentioning

confidence: 90%

“…The corresponding KÀ L plots (inset in Figure 3d) exhibited a perfect linearity over the potential range of 0.4-0.6 V, suggesting first-order reaction kinetics to oxygen concentration and similar electron-transfer numbers for ORR at different electrode potentials. [45][46][47] In addition, RRDE measurements were carried out to acquire a more accurate electron-transfer number as well as the yield of H 2 O 2 (Figure 3e). From 0.4 to 0.8 V, the electron transfer number of FeÀ NÀ C/700 were above 3.84 and the yield of H 2 O 2 was below 7.9 %.…”

Section: Resultsmentioning

confidence: 99%

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Synthesis of Tangled Iron‐Nitrogen Co‐doped Carbon Nanosheets through a Dopamine Coordination Strategy for the Oxygen Reduction Reaction

Qin

Zhu

et al. 2021

ChemElectroChem

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Developing efficient, economical, and durable transition metal atom‐dispersed catalysts to boost the sluggish oxygen reduction reactions (ORRs) is crucial for the practical metal‐air batteries. Herein, a facile dopamine‐coordination strategy was developed to obtain tangled Fe, N co‐doped ultrathin carbon nanosheets (donated as tangled Fe−N−C nanosheets), which can be utilized as high‐performance ORR electrocatalysts. Benefited from the unique hierarchical porous structures and abundant Fe−Nx active sites, the tangled Fe−N−C nanosheets exhibited excellent ORR activity in alkaline medium with more positive half‐wave potential (0.88 V vs. RHE) than 20 wt % Pt/C (0.84 V vs. RHE). Meanwhile, the tangled Fe−N−C nanosheets exhibit excellent long‐term stability and good tolerance to methanol crossover. When applying the Fe−N−C nanosheets as the cathode catalyst for primary zinc‐air batteries (ZABs), the assembled cells exhibit high open circuit voltage (∼1.43 V), high peak power density (∼89 mW cm−2) and large specific capacity of 801 mA h g−1.

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Section: Resultsmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Synthesis of Tangled Iron‐Nitrogen Co‐doped Carbon Nanosheets through a Dopamine Coordination Strategy for the Oxygen Reduction Reaction

Qin

Zhu

et al. 2021

ChemElectroChem

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“…Not even the volcano-type dependence of E 1/2 from (C–S–C)/Fe ratio proposed by Ni et al finds confirmation in the sulfur-doped series. 72 …”

Section: Resultsmentioning

confidence: 99%

Sulfur Doping versus Hierarchical Pore Structure: The Dominating Effect on the Fe–N–C Site Density, Activity, and Selectivity in Oxygen Reduction Reaction Electrocatalysis

Daniel

Mazzucato

Brandiele

et al. 2021

ACS Appl. Mater. Interfaces

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Nitrogen doping has been always regarded as one of the major factors responsible for the increased catalytic activity of Fe–N–C catalysts in the oxygen reduction reaction, and recently, sulfur has emerged as a co-doping element capable of increasing the catalytic activity even more because of electronic effects, which modify the d-band center of the Fe–N–C catalysts or because of its capability to increase the Fe–N x site density (SD). Herein, we investigate in detail the effect of sulfur doping of carbon support on the Fe–N x site formation and on the textural properties (micro- and mesopore surface area and volume) in the resulting Fe–N–C catalysts. The Fe–N–C catalysts were prepared from mesoporous carbon with tunable sulfur doping (0–16 wt %), which was achieved by the modulation of the relative amount of sucrose/dibenzothiophene precursors. The carbon with the highest sulfur content was also activated through steam treatment at 800 °C for different durations, which allowed us to modulate the carbon pore volume and surface area (1296–1726 m 2 g –1 ). The resulting catalysts were tested in O 2 -saturated 0.5 M H 2 SO 4 electrolyte, and the site density (SD) was determined using the NO-stripping technique. Here, we demonstrate that sulfur doping has a porogenic effect increasing the microporosity of the carbon support, and it also facilitates the nitrogen fixation on the carbon support as well as the formation of Fe–N x sites. It was found that the Fe–N–C catalytic activity [ E 1/2 ranges between 0.609 and 0.731 V vs reversible hydrogen electrode (RHE)] does not directly depend on sulfur content, but rather on the microporous surface and therefore any electronic effect appears not to be determinant as confirmed by X-ray photoemission spectroscopy (XPS). The graph reporting Fe–N x SD versus sulfur content assumes a volcano-like shape, where the maximum value is obtained for a sulfur/iron ratio close to 18, i.e., a too high or too low sulfur doping has a detrimental effect on Fe–N x formation. However, it was highlighted that the increase of Fe–N x SD is a necessary but not sufficient condition for increasing the catalytic activity of the material, unless the textural properties are also optimized, i.e., there must be an optimized hierarchical porosity that facilitates the mass transport to the active sites.

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“…Moreover, it is widely accepted that the transition metals, especially Fe and Ni, can introduce N and S atoms into the carbon lattice during high‐temperature pyrolysis. [ 46–48 ] Furthermore, the formation of M–N x active sites can further induce the formation of thiophene S around them. Consequently, the content of S in the Fe–Ni ANC@NSCA catalysts (8.4 wt%) is higher than that in other two samples, which is also approximately equal to the sum of the content of S in the Fe NC@NSCA catalysts (4.15 wt%) and the Ni NP@NSCA catalysts (3.84 wt%), based on the contents of Fe and Ni among them.…”

Section: Resultsmentioning

confidence: 99%

Fe–Ni Alloy Nanoclusters Anchored on Carbon Aerogels as High‐Efficiency Oxygen Electrocatalysts in Rechargeable Zn–Air Batteries

Shu

Tong

et al. 2021

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In this work, Fe–Ni alloy nanoclusters (Fe–Ni ANCs) anchored on N, S co‐doped carbon aerogel (Fe–Ni ANC@NSCA catalysts) are successfully prepared by the optimal pyrolysis of polyaniline (PANI) aerogels derived from the freeze‐drying of PANI hydrogel obtained by the polymerization of aniline monomers in the co‐presence of tannic acid (TA), Fe3+, and Ni2+ ions. In addition, the optimal molar ratio of the TA, Fe3+, and Ni2+ ions for synthesis of Fe–Ni ANC@NSCA catalysts are 1:2:5, which can guarantee the formation of carbon aerogel composed of quasi‐2D porous carbon sheets and the formation of high‐density Fe–Ni ANCs with an ultrasmall size between 2 to 2.8 nm. These Fe–Ni ANCs consisting of N4–Fe–O–Ni–N4 moiety are proposed as a new type of active species for the first time, to the best of the authors’ knowledge. Thanks to their unique features, the Fe–Ni ANC@NSCA catalysts show excellent performance in oxygen reduction reaction with a half‐wave potential (E1/2) of 0.891 V and oxygen evolution reaction (260 mV @ 10 mA cm−2) in alkaline media as bifunctional catalysts, which are better than the state‐of‐the‐art commercial Pt/C catalysts and RuO2 catalysts. Moreover, Zn–air battery assembled with the Fe–Ni ANC@NSCA catalysts also shows a remarkable performance and exceptionally high stability over 500 h at 5 mA cm−2.

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Optimized Enhancement Effect of Sulfur in Fe–N–S Codoped Carbon Nanosheets for Efficient Oxygen Reduction Reaction

Cited by 54 publications

References 52 publications

Synthesis of Tangled Iron‐Nitrogen Co‐doped Carbon Nanosheets through a Dopamine Coordination Strategy for the Oxygen Reduction Reaction

Synthesis of Tangled Iron‐Nitrogen Co‐doped Carbon Nanosheets through a Dopamine Coordination Strategy for the Oxygen Reduction Reaction

Sulfur Doping versus Hierarchical Pore Structure: The Dominating Effect on the Fe–N–C Site Density, Activity, and Selectivity in Oxygen Reduction Reaction Electrocatalysis

Fe–Ni Alloy Nanoclusters Anchored on Carbon Aerogels as High‐Efficiency Oxygen Electrocatalysts in Rechargeable Zn–Air Batteries

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