Mohammad Razaul Karim, Kazuto Hatakeyama, Takeshi Matsui, Hiroshi Takehira et al.
We measured the proton conductivity of bulk graphite oxide (GO'), a graphene oxide/proton hybrid (GO-H), and a graphene oxide (GO) nanosheet for the first time. GO is a well-known electronic insulator, but for proton conduction we observed the reverse trend, as it exhibited superionic conductivity. ...
Kazuto Hatakeyama, Mohammad Razaul Karim, Chikako Ogata, Hikaru Tateishi et al.
Graphene oxide (GO) walled channels filled by sulfate ions exhibit an optimized proton conductivity, which is higher than the proton conductivity of all other forms of GO. The sulphate ion increases the water absorbing capacity and hydrogen bond reformation process in GO.
Mohammad Razaul Karim, Md. Saidul Islam, Kazuto Hatakeyama, Masaaki Nakamura et al.
The effect of interlayer distance and oxygen content on proton conductivity of graphite oxide is presented. Bulk-state proton conductivities were measured using coin-shaped pellets of three different graphite oxide samples, namely, H-GO, S-GO, and B-GO, generated respectively from the techniques of ...
Mohammad Razaul Karim, Hideaki Shinoda, Mina Nakai, Kazuto Hatakeyama et al.
Abstract The rare coexistence of ferromagnetism and electrical conductivity is observed in the reduced graphene oxide–metal oxide hybrids, rGO‐Co, rGO‐Ni, and rGO‐Fe, using chemical reduction with hydrazine or ultraviolet photoirradiation of the graphene oxide–metal complexes, GO‐Co, GO‐Ni, and GO‐F...
Mohammad Razaul Karim, Kazuto Hatakeyama, Michio Koinuma, Shinya Hayami
Proton conductors are necessary in fuel cells, hydrogen separation, steam electrolysis, sensors and biological transport systems. Advances in the development of proton conductors from carbon allotropes, perovskites, ceramics and metal organic frameworks have been reviewed.
Kosuke Wakata, Md. Saidul Islam, Mohammad Razaul Karim, Kazuto Hatakeyama et al.
The role of hydrophilic groups in acid intercalated GO for proton conduction has been justified. The higher extents of adsorbed water due to the presence of hydrophilic groups are primarily responsible for offering enhanced proton conductivity.
Yukino Ikeda, Mohammad Razaul Karim, Hiroshi Takehira, Takeshi Matsui et al.
Abstract Proton conductivity of graphene oxide (GO) has been reduced in graphene oxide–metal ion hybrids (GO–M; M = K+, Al3+, Zn2+, Fe3+, Cr3+, Co2+, Pr3+, Ce3+, and Tb3+). As the hybrids contain doped metal ions, we propose their possibility as catalyst and electrodes in sensing devices.
Md. Saidul Islam, Mohammad Razaul Karim, Kazuto Hatakeyama, Hiroshi Takehira et al.
A highly stable proton conductor has been developed from carbon sphere oxide (CSO). Carbon sphere (CS) generated from sucrose was oxidized successfully to CSO using Hummers' graphite oxidation technique. At room temperature and 90 % relative humidity, the proton conductivity of thin layer CSO on mic...
Yukino Ikeda, Mohammad Razaul Karim, Hiroshi Takehira, Kazuto Hatakeyama et al.
Abstract We report the photocatalytic activities of graphene oxide–alkylated amines (GO–An; GO: graphene oxide and An: alkylamine with n carbons in the alkyl group; n = 0, 1, 4, and 8). The hybrids were synthesized through facile, quick, and reproducible methods and were characterized by Fourier tra...
Mohammad Atiqur Rahman, Satsuki Tomatsu, Kazuto Hatakeyama, Shintaro Ida
Layered double hydroxides (LDHs) have emerged as promising solid state hydroxide ion (OH − ) conductors owing to their tunable composition, 2D layered architecture, and high anion exchange capability. However, their practical implementation as electrolytes in fuel cells has long been impeded by the ...