Photo-exited carrier dynamics in the photo-catalyst phenomena by time-resolved terahertz attenuated total reflection spectroscopy

• Project/Area Number: 18K04836
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 27030:Catalyst and resource chemical process-related
• Research Institution: Osaka University
• Principal Investigator: Watanabe Hiroshi 大阪大学, 生命機能研究科, 助教 (50625316)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2018: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: 光触媒 / 時間分解分光 / THz分光 / 光触媒反応 / 時間分解テラヘルツ分光 / 時間分解測定 / 光物性

Outline of Final Research Achievements

We measured time-resolved terahertz attenuated total reflection (THz-ATR) spectroscopy measurements on the photocatalyst [Re(CO)2(bpy){P(OEt)3}2](PF6) and observed charge transfer dynamics from the reducing agent TEOA to the Re complex after laser irradiation. The intermolecular vibration mode between TEOA and Re complex at 1.35 THz shifted to 1.7 THz 9 ps after light irradiation. This indicates that we succeeded in observing that TEOA approaches the Re complex as a precursor phenomenon of charge transfer from TEOA to the Re complex. As the resurts, we succeeded in observing not only the charge transfer phenomena but also the molecular movement of TEOA before the charge transfer by using a new method called time-resolved THz-ATR spectroscopy.

Academic Significance and Societal Importance of the Research Achievements

近年人類が直面しているエネルギーにかかわる2つの大きな問題、化石燃料の枯渇、および二酸化炭素の増加に伴う地球温暖化の問題を同時に解決する手段として人工光合成などの光触媒反応の研究が進んでいる。人工光合成反応において二酸化炭素の還元反応の高効率化が最も重要な課題であり、その為には光励起された電子ダイナミクスを明らかにする必要がある。我々が行った時間分解THz全反射分光という手法は液体中の分子間距離の時間変化を知ることができ、光反応過程において電荷移動反応の前駆現象として金属分子と還元剤の距離が縮まる様子を観測した。このことは触媒反応の高効率化する上で重要な役割を果たすと考えられる。

Research Products

• [Journal Article] Relaxation dynamics of [Re(CO)2(bpy){P(OEt)3}2](PF6) in TEOA solvent measured by time-resolved attenuated total reflection terahertz spectroscopy (2019)
  • Author(s): Nguyen Phuong Ngoc、Watanabe Hiroshi、Tamaki Yusuke、Ishitani Osamu、Kimura Shin-ichi
  • Journal Title: Scientific Reports Volume: 9 Issue: 1 Pages: 11772-11772
  • DOI: 10.1038/s41598-019-48191-4
  • Peer Reviewed / Open Access
• [Presentation] Time resolved attenuated total reflection spectroscopy on photo catalyst [Re(CO)2(bpy){P(OEt)3}2](PF6) (2020)
  • Author(s): H. Watanabe, PN. Nguyen, Y. Tamaki, O. Ishitani, and S. Kimura
  • Organizer: LSC 2020
  • Int'l Joint Research / Invited
• [Presentation] 光触媒[Re(CO)2(bpy)(P(OEt)3)2](PF6)における超高速テラヘルツ分光 (2019)
  • Author(s): 渡邊浩、Phuong Ngoc Nguyen,、玉置悠祐、石谷治、木村真一
  • Organizer: 日本物理学会 第74回年次大会
• [Presentation] Relaxation dynamics in [Re(CO)2(bpy)(P(OEt)3)2]+(PF6)- in TEOA solvent measured by time-resolved ATR THz spectroscopy (2018)
  • Author(s): Phuong Ngoc Nguyen, Hiroshi Watanabe, Yusuke Tamaki, Osamu Ishitani, Shin-ichi Kimura
  • Organizer: 日本物理学会 2018年秋季大会
• [Remarks] 光触媒反応中の電子と分子の超高速な動きを世界初観測
  • URL: https://www.titech.ac.jp/news/pdf/tokyotechpr20190828_ishitani_1_pg41w1ow.pdf
• [Remarks] 光触媒反応中の電子と分子の超高速な動きを世界初観測
  • URL: https://www.titech.ac.jp/news/2019/045055.html