DEPARTMENT OF
PHYSICAL CHEMISTRY
Physikalische Chemie - Direktor: Prof. Dr. Martin Wolf
Department Seminar
Host: T. Kumagai

Monday, March 11, 2019, 11:00 am
All are invited to meet around 10:40 am for a chat with coffee & cookies.
PC Seminar Room, G 2.06, Faradayweg 4
Assist. Prof. Takaya Ogawa
Socio-Environmental Energy Science Department, Graduate School of Energy Science, Kyoto University
Proton conduction mechanism in a material consisting of packed-acids and a material design toward the proton conductivity with low dependence on humidity
PCseminarabstr_190311
Aqueous proton conduction has been investigated as a versatile phenomenon in acid-base chemistry and most biological redox reactions. Especially, proton conducting membranes, such as Nafion has been studied intensively for the application of polymer electrolyte fuel cell (PEFC). The electrolytes have a drawback that proton conductivity severely decreases at low humidity, which leads negative effect on energy efficiency and cost. The drawback is derived from the conventional mechanism of proton conduction, vehicle mechanism or structural diffusion. The rate-determining step of proton conduction is cleavage of hydrogen bonds, which is usually caused by thermal vibration of water. Therefore, the movement of water is indispensable and humidity is required for high proton conductivity.
In this seminar, the novel mechanism “packed-acid mechanism”, which occurs in a material with concentrated acids will be presented using ab initio calculation and experiments. The packed-acid mechanism causes the cleavage of hydrogen bonds by acid-acid interaction without water movement, indicated by the calculations [1]. From the measurement of low temperature NMR, it was observed that proton in an ordinary proton conducting material did not move below the water- freezing temperature, whereas proton remained active in the material where packed-acid mechanism occurs [2]. It means that packed-acid mechanism does not require water movement to conduct proton. Using ab initio calculation, a material design to facilitate the packed-acid mechanism will be proposed in this presentation. Eventually, the material which conducts proton through the packed-acid mechanism showed a proton conductivity with low dependence on humidity.
In addition, a useful tool to produce academic collaborations will be presented using computational method based on biblioimetrics [3]. I will show the case study of fuel cell and ammonia synthesis.
[1] Ogawa, T.; Aonuma, T.; Tamaki, T.; Ohashi, H.; Ushiyama, H.; Yamashita, K.; Yamaguchi, T., Chem. Sci. 2014, 5 (12), 4878-4887..
[2] Ogawa, T.; Kamiguchi, K.; Tamaki, T.; Imai, H.; Yamaguchi, T., Anal. Chem. 2014, 86 (19), 9362-9366. [3] Ogawa, T.; Kajikawa, Y., Technol. Forecast. Soc. Change 2017, 120, 41-47.