Interfacial Electron Transfer Dynamics Following Laser Flash Photolysis of [Ru(bpy)2((4,4′-PO3H2)2bpy)]2+ in TiO2 Nanoparticle Films in Aqueous Environments
Interfacial Electron Transfer Dynamics Following Laser Flash Photolysis of [Ru(bpy)2((4,4′-PO3H2)2bpy)]2+ in TiO2 Nanoparticle Films in Aqueous Environments
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DOI：
10.1002/cssc.201000356
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发表时间：
2011-01-01
期刊：
影响因子：
8.4
通讯作者：
Meyer, Thomas J.
中科院分区：
文献类型：
--
作者：
Brennaman, M. Kyle;Patrocinio, Antonio Otavio T.;Meyer, Thomas J.
利用纳秒激光光解技术研究了[（Ru-（bpy）（2）（4，4 '-（PO_3H_2）（2）bpy）]（2+）与TiO_2（TiO_2-Ru-II）表面结合的电子注入和背电子转移。在适合于通过已知的单位点水氧化催化剂进行水氧化催化的条件下进行测量。背电子转移的平均寿命的系统变化，-观察到pH值的变化，表面覆盖率，入射激发强度，和施加的偏压。结果定性地与一个模型相一致，该模型涉及从陷阱位置到导带或浅陷阱位置的注入电子的限速热激活，随后是位置到位置的跳跃和界面电子转移，TiO 2（e（-））-Ru 3 + -> TiO 2-Ru 2+。pH依赖性的外观减少的效率形成的TiO 2-Ru 3+和入射光子-电流效率与添加的还原清除剂氢醌点pH依赖性的背电子转移过程的亚纳秒和毫秒-微秒的时间尺度上，这可能是显着的限制长期存储的多个氧化还原当量。
Nanosecond laser flash photolysis has been used to investigate injection and back electron transfer from the complex [(Ru-(bpy)(2)(4,4'-(PO3H2)(2)bpy)](2+) surface-bound to TiO2 (TiO2-Ru-II). The measurements were conducted under conditions appropriate for water oxidation catalysis by known single-site water oxidation catalysts. Systematic variations in average lifetimes for back electron transfer, - were observed with changes in pH, surface coverage, incident excitation intensity, and applied bias. The results were qualitatively consistent with a model involving rate-limiting thermal activation of injected electrons from trap sites to the conduction band or shallow trap sites followed by site-to-site hopping and interfacial electron transfer, TiO2(e(-))-Ru3+ -> TiO2-Ru2+. The appearance of pH-dependent decreases in the efficiency of formation of TiO2-Ru3+ and in incident-photon-to-current efficiencies with the added reductive scavenger hydroquinone point to pH-dependent back electron transfer processes on both the sub-nanosecond and millisecond-microsecond time scales, which could be significant in limiting long-term storage of multiple redox equivalents.