Photocatalitic mechanism at the interface between quasi-liquid water layer and well-defined oxides

2015 Fiscal Year Final Research Report

• Project/Area Number: 26810006
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Physical chemistry
• Research Institution: Kyoto University
• Principal Investigator: Tohsiki Sugimto 京都大学, 理学(系)研究科(研究院), 助教 (00630782)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 水分解-水素酸素発生光触媒 / 光誘起電荷ダイナミクス / 赤外拡散反射分光 / 表面吸着水

Outline of Final Research Achievements

We show that NiOx nanoparticles loaded on a layered perovskite, BaLa4Ti4O15 (BLT), serve as an effective electron sink. Fittings of the decay profiles of TA at402 nm with a trap detrap kinetic model indicate that the oxidation of water appreciably starts at around 1 ms after the pump pulse, while the duction of water takes place prior to oxidation in much early time domains. This implies that the redox reactions take place under substantial imbalance between electron and hole densities.
In addition, we have performed infrared transient and steady-state absorption spectroscopy of anatase TiO2 nanoparticles as a function of the number of water
adsorbate layers. We have demonstrated that water molecules reversibly adsorbed in the first layer on TiO2 nanoparticles are capable to trap photogenerated holes, while water in the second layer hydrogen bonding to the first-layer water makes hole trapping less effective.

Free Research Field

物理化学