Interfacial electron transfer in metal cyanide-sensitized TiO2 nanoparticles.
Interfacial electron transfer in metal cyanide-sensitized TiO2 nanoparticles.
复制标题
金属氰化物敏化 TiO2 纳米颗粒中的界面电子转移。
DOI：
10.1021/jp0679313
复制
发表时间：
2007
影响因子：
3.3
通讯作者：
B. Brunschwig
中科院分区：
文献类型：
--
作者：
J. Harris;K. Trotter;B. Brunschwig
采用电吸收（Stark）光谱法研究了过渡金属氰化物配合物对TiO2纳米颗粒的电荷转移吸收。采用FeII(CN)(6)4-、RuII(CN)6（4-）、MoIV(CN)(8)4-和WIV(CN)8（4-）合成过渡金属氰化物/TiO2（颗粒）体系。在M(CN)n4-/TiO2（粒子）体系形成后，在390 ~ 480nm区域出现了新的金属-粒子电荷转移（MPCT）吸收带。吸收光谱分析表明，参与MPCT跃迁的TiO2能级位于明显高于导带底部的能量，两个金属中心之间的电子耦合是决定MPCT带最大值位置的主要因素。斯塔克光谱测定的平均电荷转移距离为4.1 ~ 4.7 A。观察到相对较短的电荷转移距离，可以得出结论，MPCT吸收是从过渡金属氰化物中心到定位在[O2Ti-N-C-M(CN)x]体系氮端结合的Ti原子上的水平。为双态模型计算的电子耦合Hab与在双核金属配合物中观察到的值相似。
Electroabsorption (Stark) spectroscopy has been used to study the charge-transfer absorption from a transition-metal-cyanide complex to a TiO2 nanoparticle. Transition-metal cyanide/TiO2(particle) systems were synthesized using FeII(CN)(6)4-, RuII(CN)6(4-), MoIV(CN)(8)4-, and WIV(CN)8(4-). On formation of the M(CN)n4-/TiO2(particle) system, a new metal-to-particle charge-transfer (MPCT) absorption band is observed in the 390-480 nm region. Analysis of the absorption spectra suggests that the TiO2 level involved in the MPCT transition resides at significantly higher energy than the bottom of the conduction band and that the electronic coupling between the two metal centers is the dominant factor determining the position of the MPCT band maximum. The average charge-transfer distances determined by Stark spectra range from 4.1-4.7 A. The observation of relatively short charge-transfer distances leads to the conclusion that the MPCT absorption is from the transition-metal cyanide center to a level that is localized on the Ti atom bound to a nitrogen end of the [O2Ti-N-C-M(CN)x] system. The electronic coupling, Hab, calculated for a two state model is similar to values observed in dinuclear metal complexes.