One-electron redox processes during polyoxometalate-mediated photocatalytic reactions of TiO2 studied by two-color two-laser flash photolysis
One-electron redox processes during polyoxometalate-mediated photocatalytic reactions of TiO2 studied by two-color two-laser flash photolysis
复制标题
DOI：
10.1002/chem.200501077
复制
发表时间：
2006-04-03
影响因子：
4.3
通讯作者：
Majima, T
中科院分区：
文献类型：
--
作者：
Tachikawa, T;Tojo, S;Majima, T
采用双色双激光闪光光解技术研究了多氧杂多酸（POM）介导的TiO 2光催化反应中几种化合物的单电子氧化还原过程。发现由于电子从TiO 2的导带（CB）转移到POM，被捕获的空穴（h（tr）（+））或表面结合的OH自由基（OHs中心点）的芳香硫化物的单电子氧化的效率显著增强。从TiO_2的CB到POM的电子转移效率按H_2 W_（12）O_（40）~（6-）<Si_（12）O_（40）~（4-）<PW_（12）O_（40）~（3-）的顺序降低，即它取决于POM的还原电位（E-red）。利用双色双激光闪光光解技术，清晰地观察到激发态PW 12 O 404-（PW 12 O 404-*）向TiO 2 CB的电子注入。在双色双激光照射下，实现了TiO_2/PW_（12）O_（40）3-/甲基紫精（MV ~（2+））三元体系的电子存储。
The one-electron redox processes of several compounds during polyoxometalate (POM)-mediated photocatalytic reactions of TiO2 were investigated using the two-color two-laser flash-photolysis technique. The efficiency of the one-electron oxidation of aromatic sulfides by the trapped hole (h(tr)(+)) or the surface-bound OH radical (OHs center dot) is found to be significantly enhanced due to electron transfer from the conduction band (CB) of TiO2 to the POM. The efficiency of the electron transfer from the CB of TiO2 to the POM decreases in the order H2W12O406- < SiW12O404- < PW12O403- that is, it depends on the reduction potential (E-red) of the POMs. Electron injection from PW12O404- in the excited state (PW12O404-*) to the CB of TiO2 was clearly observed using the two-color two-laser flash-photolysis technique. Storage of electrons in the TiO2/PW12O403-/methyl viologen (MV2+) ternary system was also achieved upon two-color two-laser irradiation.