Ion conduction switching between H<sup>+</sup> and OH<sup>−</sup> induced by pH in graphene oxide

Fukuda, Masahiro; Islam, Md. Saidul; Shudo, Yuta; Yagyu, Junya; Lindoy, Leonard F.; Hayami, Shinya

doi:10.1039/d0cc00769b

Cited by 18 publications

(18 citation statements)

References 29 publications

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“…To solve this issue, many polymer‐, double‐layered hydroxide‐, or graphene oxide‐based electrolytes have been intensively studied. [ 12–15 ] In particular, trimethyl ammonium‐functionalized polystyrenes (TMA‐70) exhibit high ion‐exchange capacity (IEC) (3.3 mequiv. ), and hexamethyl trimethyl ammonium‐functionalized Diels–Alder polyphenylene (HTMA‐DAPP) showed a conductivity of 1.20 × 10 –1 S cm –1 at 80 °C under fully hydrated conditions.…”

Section: Introductionmentioning

confidence: 99%

Emerging Porous Solid Electrolytes for Hydroxide Ion Transport

Kang

et al. 2021

Adv Funct Materials

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Anion exchange membrane fuel cells (AEMFCs) offer several advantages over proton exchange membrane fuel cells, such as the use of a non‐precious metal catalyst, but these cells suffer from various issues related to OH–‐conducting electrolytes, including low conductivity and the formation of K2CO3 salt. These issues need to be resolved for the widespread use of AEMFCs. Recently, many studies have focused on developing excellent ion‐conductive electrolytes using porous materials based on metal–organic and covalent organic frameworks. However, most of this research is biased toward proton‐conducting electrolytes; to the best of the authors’ knowledge, reviews addressing OH–‐conducting electrolytes using porous materials have not been reported thus far. This review discusses OH–‐conducting porous crystalline materials and their membranes in terms of different synthetic strategies, conduction mechanisms, and experimental modalities for the design and development of future anion conductive electrolytes in fuel cells.

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Section: Introductionmentioning

confidence: 99%

Emerging Porous Solid Electrolytes for Hydroxide Ion Transport

Kang

et al. 2021

Adv Funct Materials

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“…The nature of the conducting ionic species in 3DGO was confirmed using the isotope effect; the conductivity of H 2 O-humidified 3DGO was almost 1.2−1.5 times higher than that for D 2 O-humidified 3DGO (Figure S7), thus indicating that the ionic species involved in the conduction in 3DGO are protons. 26,27 The proton conductivities of the GO membrane and 3DGO were also measured in the in-plane direction. The RH − -dependent and temperature-dependent proton conductivities are shown in Figure 2c,d, respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Enhanced Fuel Cell Performance Using Ultrafast, Out-of-Plane Proton-Conducting, 3D Graphene Oxide as an Electrolyte

Yagyu

Islam

Shudo

et al. 2021

ACS Appl. Energy Mater.

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Despite the considerable in-plane proton conductivity of graphene oxide (GO) nanosheets, inadequate single-cell performance in a polymer exchange membrane fuel cell (PEMFC) occurred on incorporating a vacuum-filtration-prepared GO membrane between the electrodes. In particular, the proton transfer between the electrodes in the PEMFC single cell is in the out-of-plane direction of the GO membrane and was found to be significantly lower than for the in-plane direction due to the presence of proton conduction barriers arising from turbostratic stacking of the GO layers. Therefore, the structural transformation of GO nanosheets into an ultrafast, out-of-plane proton conductor is key to boosting GO-based PEMFC performance. Here, we report the use of a freeze-dried route to three-dimensional (3D) graphene oxide (3DGO) exhibiting a 3D interconnected network and significant interlayer void space. The out-of-plane direction proton conductivity of 3DGO was calculated to be 3.5 × 10–2 S cm–1 at 343 K and 100% relative humidity (RH), which is about 175 times higher than that for the GO membrane. The 3DGO was incorporated as a solid electrolyte in a PEMFC single cell, and a maximum power density of 60.2 mW cm–2 was obtained at 30 °C. This high proton conductivity and PEMFC performance of the 3DGO are correlated with the facile proton conduction pathway and higher water uptake in the 3D porous architecture of 3DGO.

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“…Over recent decades, GO‐based materials have been demonstrated to have widespread applications in chemistry, physics, biology, electronics, engineering, and medicine. For example, particular GO materials have been demonstrated to display proton conduction, semi‐conductivity, light emission, and to act as catalysts [9–14] . They have also been used for drug delivery as well as for sensor and transistor fabrication [15,16] .…”

Section: Figurementioning

confidence: 99%

“…For example, particular GO materials have been demonstrated to display proton conduction, semi-conductivity, light emission, and to act as catalysts. [9][10][11][12][13][14] They have also been used for drug delivery as well as for sensor and transistor fabrication. [15,16] In the current work we were successful in achieving a phase transition of pure GO to diamond by the high temperature/ high pressure method using a 2000-ton Kawai type multi-anvil apparatus (Ehime University ORANGE-2000).…”

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Crystallization of Diamond from Graphene Oxide Nanosheets by a High Temperature and High Pressure Method

et al. 2021

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Herein we report a high temperature and high pressure driven crystallization of two-dimensional graphene oxide (GO) nanosheets to three-dimensional diamond. The successful phase transformation was confirmed using X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The phase transition platform will available to utilize for a wide variety of diamond doping employing, for example, nitrogen or other light elements, in which the correspondingly doped GO is used as the starting material.

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Ion conduction switching between H⁺ and OH⁻ induced by pH in graphene oxide

Abstract: Ion conduction through graphene oxide nanosheets that is pH-switchable between H+ and OH− ions is demonstrated.

Cited by 18 publications

References 29 publications

Emerging Porous Solid Electrolytes for Hydroxide Ion Transport

Emerging Porous Solid Electrolytes for Hydroxide Ion Transport

Enhanced Fuel Cell Performance Using Ultrafast, Out-of-Plane Proton-Conducting, 3D Graphene Oxide as an Electrolyte

Crystallization of Diamond from Graphene Oxide Nanosheets by a High Temperature and High Pressure Method

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Ion conduction switching between H+ and OH− induced by pH in graphene oxide

Abstract: Ion conduction through graphene oxide nanosheets that is pH-switchable between H+ and OH− ions is demonstrated.

Cited by 18 publications

References 29 publications

Emerging Porous Solid Electrolytes for Hydroxide Ion Transport

Emerging Porous Solid Electrolytes for Hydroxide Ion Transport

Enhanced Fuel Cell Performance Using Ultrafast, Out-of-Plane Proton-Conducting, 3D Graphene Oxide as an Electrolyte

Crystallization of Diamond from Graphene Oxide Nanosheets by a High Temperature and High Pressure Method

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Ion conduction switching between H⁺ and OH⁻ induced by pH in graphene oxide