Advantage of semi-ionic bonding in fluorine-doped carbon materials for the oxygen evolution reaction in alkaline media

Kim, Jeheon; Zhou, Ronggang; Murakoshi, Kei; Yasuda, Satoshi

doi:10.1039/c8ra01636d

Cited by 49 publications

(37 citation statements)

References 21 publications

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“…The enhanced OER performance after F‐doping was ascribed to the resulting high positive charge on carbon atoms, which could guarantee fast adsorption and exchange of O 2 , OH − , and H 2 O species throughout the OER process. [ 52 ] The electrochemical impedance spectroscopy measurements confirmed that the charge‐transfer resistance ( R ct ) of NPF‐CNS‐2 was much smaller than the IrO 2 and other samples, indicated faster kinetics of the OER for NPF‐CNS‐2 (Figure S27, Supporting Information). A small catalytic degradation was observed in the chronoamperometry ( i – t ) curve for continuous test over 50 000 s, suggesting that NPF‐CNS‐2 had good OER long‐term stability (Figure 5c).…”

Section: Resultsmentioning

confidence: 96%

“…According to the literature, both of these bonds were associated with high ORR/OER electrocatalytic activity. [26,[51][52][53] Moreover, the surface wettability of the catalysts before and after F-doping was investigated by contact angle measurements ( Figure S12, Supporting Information). The measured contact angles of NP-CNS and NPF-CNS-2 are 70.1° and 27.9°, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Metal‐Free Multi‐Heteroatom‐Doped Carbon Bifunctional Electrocatalysts Derived from a Covalent Triazine Polymer

Zheng

Song

Chen

et al. 2020

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The construction of multi‐heteroatom‐doped metal‐free carbon with a reversibly oxygen‐involving electrocatalytic performance is highly desirable for rechargeable metal‐air batteries. However, the conventional approach for doping heteroatoms into the carbon matrix remains a huge challenge owing to multistep postdoping procedures. Here, a self‐templated carbonization strategy to prepare a nitrogen, phosphorus, and fluorine tri‐doped carbon nanosphere (NPF‐CNS) is developed, during which a heteroatom‐enriched covalent triazine polymer serves as a “self‐doping” precursor with C, N, P, and F elements simultaneously, avoiding the tedious and inefficient postdoping procedures. Introducing F enhances the electronic structure and surface wettability of the as‐obtained catalyst, beneficial to improve the electrocatalytic performance. The optimized NPF‐CNS catalyst exhibits a superb electrocatalytic oxygen reduction reaction (ORR) activity, long‐term durability in pH‐universal conditions as well as outstanding oxygen evolution reaction (OER) performance in an alkaline electrolyte. These superior ORR/OER bifunctional electrocatalytic activities are attributed to the predesigned heteroatom catalytic active sites and high specific surface areas of NPF‐CNS. As a demonstration, a zinc‐air battery using the NPF‐CNS cathode displays a high peak power density of 144 mW cm−2 and great stability during 385 discharging/charging cycles, surpassing that of the commercial Pt/C catalyst.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Metal‐Free Multi‐Heteroatom‐Doped Carbon Bifunctional Electrocatalysts Derived from a Covalent Triazine Polymer

Zheng

Song

Chen

et al. 2020

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143

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“…The integrated peak area ratio of sp 2 ‐C versus sp‐C is 1.0, in accordance with the chemical composition of p‐FGDY. The fluorine peak (687.4 eV, Figure j) can be ascribed to the semi‐ionic C−F bond with high polarity, which enhances the catalytic activity . This is further verified by our density functional theory (DFT) results (discussed later).…”

Section: Resultsmentioning

confidence: 91%

Fluorographdiyne: A Metal‐Free Catalyst for Applications in Water Reduction and Oxidation

et al. 2019

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Ah ighly efficient bifunctional metal-free catalyst was prepared by growth of three-dimensional porous fluorographdiyne networks on carbon cloth (p-FGDY/CC). Our experiments and density functional theory (DFT) calculations show the 3D p-FGDY/CC network is highly active and it is ahigh potential metal-free catalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), as well as overall water splitting (OWS) under both acidic and alkaline conditions.The experimental and theoretical results showvery good consistency;for example,inthe HER process,p-FGDY/ CC exhibits small overpotentials of 82 and 92 mV to achieve 10 mA cm À2 under alkaline and acidic conditions,respectively. This ensures an even higher selectivity for the adsorption/

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“…The C-F bonds are formed based on the fluorination reactions between carbon materials and fluorinating agents. Because the F atom has extremely strong electronegativity, fluorinated carbon involves various C-F bonding characteristics of ionic, semi-ionic, and covalent bonds [18][19][20]. Besides, based on theoretical calculation, the C-F bonds depend on the fluorination levels (F/C ratios) [15].…”

Section: Introductionmentioning

confidence: 99%

A brief review for fluorinated carbon: synthesis, properties and applications

Liu

Jiang

Wang

et al. 2019

Nanotechnology Reviews

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Fluorinated carbon (CFx), a thriving member of the carbonaceous derivative, possesses various excellent properties of chemically stable, tunable bandgap, good thermal conductivity and stability, and super-hydrophobic due to its unique structures and polar C-F bonding. Herein, we present a brief review of the recent development of fluorinated carbon materials in terms of structures, properties and preparation techniques. Meanwhile, the applications in energy conversions and storage devices, biomedicines, gas sensors, electronic devices, and microwave absorption devices are also presented. The fluorinated carbon contains various types of C-F bonds including ionic, semi-ionic and covalent C-F, C-F2, C-F3 bonds with tunable F/C ratios. The controllable designing of C-F bonding and F/C ratios play a key role to optimize the properties of fluorinated carbon materials. Until now, the potential issues and future opportunities of fluorinated carbon are proposed. The present review will provide a direction for tuning C-F bonding and F/C ratios, developing a safe and efficient fluorination method and popularizing the applications of fluorinated carbon materials.

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Advantage of semi-ionic bonding in fluorine-doped carbon materials for the oxygen evolution reaction in alkaline media

Abstract: Fluorine-doped carbon has a higher electrocatalytic oxygen evolution activity than pristine carbon black in alkaline media. The activity of oxygen evolution and characteristics of carbon to fluorine bond are controlled by pyrolysis temperature of Nafion.

Cited by 49 publications

References 21 publications

Metal‐Free Multi‐Heteroatom‐Doped Carbon Bifunctional Electrocatalysts Derived from a Covalent Triazine Polymer

Metal‐Free Multi‐Heteroatom‐Doped Carbon Bifunctional Electrocatalysts Derived from a Covalent Triazine Polymer

Fluorographdiyne: A Metal‐Free Catalyst for Applications in Water Reduction and Oxidation

A brief review for fluorinated carbon: synthesis, properties and applications

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