著者

Gabriel Alemany-Molina Beatriz Martínez-Sánchez Emilia Morallón Diego Cazorla-Amorós

出版者

The Carbon Society of Japan

雑誌

Carbon Reports (ISSN:24365831)

巻号頁・発行日

vol.1, no.4, pp.162-174, 2022-12-01 (Released:2022-12-01)

参考文献数

93

被引用文献数

2

---

Engineering the surface chemistry of carbon-based materials is of crucial importance in tuning their intrinsic properties, including electrical conductivity, wettability, electroactivity, adsorption potential, reactivity, physical and chemical stability. Intense research has recently focused on understanding the role of surface oxygen functional groups when carbon materials are in contact with an electrolyte or solvent in order to tailor and improve them for technological applications. For this purpose, their synthesis method and/or further oxidation treatments should be carefully selected, since they can substantially influence not only the oxygen content, but also the nature of the oxygen moieties, which could be decisive in determining the surface properties of the resulting material. The combined use of different chemical, spectroscopic and electrochemical techniques, provides unique and reliable information about the contribution of a specific oxygen-containing group in the surface (electro)chemistry of carbon-based materials. This paper provides a discussion of the role of oxygen heteroatoms in the surface electrochemistry of a carbon material as they relate to their influence on both its electroactivity and reactivity.

著者

Naoto Ohtsubo Syun Gohda Satoshi Sato Yasuhiro Yamada

出版者

The Carbon Society of Japan

雑誌

Carbon Reports (ISSN:24365831)

巻号頁・発行日

vol.2, no.2, pp.97-113, 2023-06-01 (Released:2023-06-01)

参考文献数

48

被引用文献数

5

---

Pyridinic nitrogen-containing carbon materials are expected to have excellent performance as electrodes and catalysts. Carbon materials containing only pyridinic nitrogen have been synthesized in recent years, and the use of two-fused-ring aromatic compounds as precursors enabled the synthesis of relatively inexpensive pyridinic nitrogen-containing carbon materials. However, a two-fused-ring aromatic compound such as isoquinoline (IQ) required a relatively high temperature (973 K) for carbonization, causing C–N bond cleavage, and the percentage of pyridinic nitrogen was relatively low: 52% of the N atoms are pyridinic. This study synthesized pyridinic nitrogen-containing carbon materials from six brominated IQs. The bromination of IQs lowered the carbonization temperatures to 673–873 K, which helped avoid the decomposition of the pyridinic nitrogen. Among these six precursors, the one with two bromine substitutions (1,4-dibromoisoquinoline) had the highest percentage of pyridinic nitrogen (65%) at 773 K. The factors that increase the percentage of pyridinic nitrogen are (1) avoiding the formation of a 1,10-phenanthroline-like structure during dimerization, (2) avoiding the formation of N–H and promoting the scission of the formed C–N in dimers formed after C=C coupling at bromine-substituted positions between precursors, and (3) forming a more ordered six-membered ring structure by the introduction of two or more highly reactive bromines.

著者

Shinji Koh Shohei Kosuga Ryosuke Suga Shunichiro Nagata Sho Kuromatsu Takeshi Watanabe Osamu Hashimoto

出版者

The Carbon Society of Japan

雑誌

Carbon Reports (ISSN:24365831)

巻号頁・発行日

vol.2, no.1, pp.23-30, 2023-03-01 (Released:2023-03-01)

参考文献数

32

被引用文献数

3

---

Transparent antennas have attracted much attention because they can meet the demands of the Internet of Things (IoT) and fifth generation (5G) mobile communication technologies. From this point of view, intensive research and development has been carried out to produce materials with high optical transparency and low electrical resistance. Research on graphene transparent antennas is reviewed along with our experimental demonstration. The unique features of graphene as a material for transparent antennas are introduced and compared to the characteristics of metal-based and metal-oxide transparent conductors. The challenges involved in the fabrication of transparent antennas using graphene films grown by chemical vapor deposition (CVD) are described. Fabrication techniques of transparent antennas (transfer and patterning methods) and techniques to decrease the sheet resistance of the graphene films (stacking and doping methods) are described. The performance of the CVD graphene transparent antennas we have fabricated are presented.