Characterization of Charge Separation in Visible Light-Sensitive TiO_2 by In-Situ ESR Spectroscopy

原位 ESR 光谱表征可见光敏感 TiO_2 中的电荷分离

• 批准号: 17550178
• 负责人: KOMAGUCHI Kenji
• 金额: $ 2.41万
• 依托单位: Hiroshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17550178/
• 关键词: Titanium dioxide; Electron spin resonance spectroscopy; Photosensitization; Photoinduced charge transfer reaction; 電荷移動錯体; 可視光応答

In-situ ESR studies were curried out to characterize paramagnetic species as the trapped electrons and notes generated and explore their transfer processes under visible light illumination in partially reduced TiO_2 and naphthol-adsorbed TiO_2 at 77 K.1. For the partially reduced pure anatase and rutile particles, a broad singlet ESR spectra due to Ti^<3+> (trapped electron) decreased in intensity upon visible light illumination, and then restored to the initial intensity in the dark. For the TiO_2 (P25) particles, however, the signal restored up to 2.5-3 times greater than before. Through the analysis of the spectral line shape, it was found that the electrons are transferred from the anatase to the rutile particles by photoexcitation in reduced TiO_2(P25).2. For O_2^- formed on partially reduced TiO_2 nanoparticles, the O2 and the surface Ti^<3+> signals were increased by 2-3 times upon illumination with visible light and reduced to the initial one by annealing the sample to r.t. in … More the dark. Assuming a reversible electron transfer reaction between Ti^<4+>-O_2^<2->-Ti^<4+> and Ti^<4+>-O_2^- + Ti^<3+>, the photoresponse was kinetically analyzed in terms of the trapping site of the O_2^- species.3. For 1-naphthol-adsorbed TiO_2 in 2-propanol suspension, electrons were transferred from the charge-transfer complex of the naphthol bound to the TiO_2 surface to be trapped as inner Ti^<3+> under visible light illumination. The signal intensity of Ti^<3+> reflected the efficiency of the photosensitization, which depended significantly on the structure of adsorbed molecules and photon energies illuminated. The kinetic analysis of the photoresponse suggested that electron trapping as surface Ti^<3+> is involved in the interfacial charge transfer process.The study demonstrated that ESR spectroscopy is useful in evaluating the charge-separation efficiency in visible light-sensitive TiO_2 and presented interesting and fundamentally important results for deepening understandings of the charge transfer processes. Less

在77 K下，利用ESR原位研究了部分还原TiO_2和萘酚吸附TiO_2在可见光照射下产生的顺磁性捕获电子和电子注，并探讨了它们在可见光照射下的转移过程。对于部分还原的纯金红石和金红石颗粒，由于Ti^<3+>（俘获电子）而产生的宽单重态ESR谱在可见光照射下强度降低，然后在黑暗中恢复到初始强度。而对于TiO_2（P25）颗粒，信号恢复到原来的2.5-3倍。通过对谱线形状的分析，发现在还原态TiO_2（P25）中，电子是通过光激发从金红石颗粒转移到金红石颗粒上的.对于在部分还原的TiO_2纳米颗粒上形成的O_2 ~+，在可见光照射下，O_2和表面Ti^<3+>信号增加了2-3倍，而在室温退火后，O_2和表面Ti^<3+>信号降低到初始值。在 ...更多信息 黑暗假设Ti^&lt;4+&gt;-O_2^<2->-Ti^&lt;4+&gt;和Ti^&lt;4+&gt;-O_2^- + Ti^&lt;3+&gt;之间存在可逆的电子转移反应，并根据O_2^-的捕获位置对光响应进行了动力学分析.在可见光照射下，1-萘酚吸附的TiO_2在异丙醇悬浮液中，电子从与表面结合的萘酚电荷转移络合物转移到TiO_2表面，被捕获为内层Ti^&lt;3+&gt;。Ti^&lt;3+&gt;的信号强度反映了光敏化的效率，而光敏化的效率与吸附分子的结构和照射的光子能量密切相关。光响应动力学分析表明，界面电荷转移过程涉及表面Ti^&lt;3+&gt;的电子俘获，ESR谱可用于评价可见光敏感TiO_2的电荷分离效率，为深入理解电荷转移过程提供了有趣而重要的结果。少

项目成果

還元したTiO_2ナノ粒子に吸着したスーパーオキシドの光反応

还原TiO_2纳米颗粒吸附超氧化物的光反应

• 发表时间: 2007
• 作者: Ewis AA;et al.;駒口健治;福岡聰・Jorg HOWE・Jorg ANDRA・Klaus BRANDENBURG;駒口健治
• 通讯作者: 駒口健治

Photochemical reaction of superoxides on the surface of titanium dioxides

二氧化钛表面超氧化物的光化学反应

• 发表时间: 2007
• 作者: T.;Maruoka;H.;Nakano;K.;Komaguchi;Y.;Harima
• 通讯作者: Harima

還元TiO_2(P25)の光励起電子移動反応

还原型TiO_2(P25)的光致电子转移反应

• 发表时间: 2005
• 作者: Satoshi Fukuoka;Joge Andra;Klaus Brandenburg;駒口健治
• 通讯作者: 駒口健治

Photoinduced electron transfer from anatase to rutile in partially reduced TiO2 (P-25) nanoparticles:: An ESR study

• DOI: 10.1016/j.cplett.2006.07.003
• 发表时间: 2006-09-20
• 期刊: CHEMICAL PHYSICS LETTERS
• 影响因子: 2.8
• 作者: Komaguchi, Kenji;Nakano, Haruka;Harima, Yutaka
• 通讯作者: Harima, Yutaka

Dual and reversible inter-conversion reactions of superoxide radical anion on TiO_2 under sub-bandgap illumination at 77 K

77 K亚带隙照明下超氧自由基阴离子在TiO_2上的双重可逆相互转化反应

• 发表时间: 2007
• 作者: T.;Maruoka;K.;Komaguchi;I.;Imae;Y.;Ooyama;Y.;Harima;福岡聰・Jorg HOWE・Jorg ANDRA・Klaus BRANDENBURG;Kenji Komaguchi
• 通讯作者: Kenji Komaguchi