研究者業績

大場 友則

オオバ トモノリ  (TOMONORI OHBA)

基本情報

所属
千葉大学 大学院理学研究院化学研究部門基盤物質化学講座 准教授
学位
博士(理学)(千葉大学)

J-GLOBAL ID
201801008722582321
researchmap会員ID
B000315293

論文

 193
  • Shunsuke Kawabata, Ryuichi Seki, Takumi Watanabe, Tomonori Ohba
    Nanomaterials 14(2) 166-166 2024年1月12日  
    Graphene is a fundamental unit of carbon materials and, thus, primary sp2-bonded carbon material. Graphene is, however, easily broken macroscopically despite high mechanical strength, although its natural degradation has rarely been considered. In this work, we evaluate the natural degradation of two-layer graphene in vacuo, in low-humidity air, and in high-humidity air at 300, 400, 450, and 500 K. Over 1000 days of degradation at 300 K, the graphene structure was highly maintained in vacuo, whereas the layer number of graphene tended to decrease in high- and low-humidity air. Water was slightly reacted/chemisorbed on graphene to form surface oxygen groups at 300 K. At 450 and 500 K, graphene was moderately volatilized in vacuo and was obviously oxidized in high- and low-humidity air. Surprisingly, the oxidation of graphene was more suppressed in the high-humidity air than in the low-humidity air, indicating that water worked as an anti-oxidizer of graphene by preventing the chemisorption of oxygen on the graphene surface.
  • Smita Takawane, Masatoshi Miyamoto, Takumi Watanabe, Tomonori Ohba
    RSC Sustainability 2024年  
    BaTiO3 nanocatalysts chemisorb and reduce CO2 efficiently at 700 K and 0.1–1.0 MPa.
  • Takumi Watanabe, Smita Takawane, Yuki Baba, Jun Akaiwa, Atsushi Kondo, Tomonori Ohba
    Journal of Physical Chemistry C 127(34) 16861-16869 2023年8月31日  
    TiO2 anatase, which exhibits the highest catalytic performance, transforms to rutile at 800 K. To inhibit the transition of anatase to rutile, several strategies, such as metal and/or non-metal doping, oxygen enrichment, and surface coating, have been studied, resulting in stable anatase within 773-1273 K. However, highly stable anatase without dopants is still required. Here, a new approach, which involves the synthesis of anatase nanocatalysts in carbon nanotubes (CNTs), was proposed to inhibit the anatase-to-rutile transition. The nanocatalysts exhibited high thermal anatase stability along with a suppression of the crystal growth up to 1200 K. The highly stable anatase in CNTs also exhibited high photocatalytic activity, which was evaluated based on methylene blue decomposition under visible- and UV-light irradiation. This was attributed to the maintenance of the small crystal size of the nanocatalysts in addition to a synergetic effect between the TiO2 nanocatalysts and CNTs.
  • Mutsuki Oikawa, Haruka Takeuchi, Daiki Chikyu, Tomonori Ohba, Zheng-Ming Wang, Setsuko Koura
    Desalination 552 116433-116433 2023年4月  査読有り
  • Takumi Watanabe, Tomonori Ohba
    Nanoscale 14(23) 8318-8325 2022年  
    Low temperature CO2 reduction and mechanism on BaTiO3 nanocatalysts from 500 K, CO2 physical adsorption at 300–500 K, CO2 chemisorption above 450 K, CO2 reduction at 500–850 K, and CO2 and CO release above 800 K.

MISC

 4

共同研究・競争的資金等の研究課題

 4