共存牺牲剂对染料敏化TiO_2纳米晶体系电子传输的影响

采用卟啉染料敏化TiO2纳米晶在可见光条件下(λ390 nm)进行水分解制氢.考察了不同牺牲剂———甲醇(MeOH)、三乙醇胺(TEOA)及其混合物对体系析氢效率的影响.通过荧光猝灭及光电化学性能分析发现,激发态染料与TiO2之间的电子转移极大地受到添加的牺牲剂的影响,而体系的pH值对其影响不大.

Influence of Co-existing Species on Charge Transfer in Dye-sensitized TiO2 Nanocrystalline System

Dye-sensitized nanocrystalline TiO2 colloidal suspensions in aqueous system were applied for H2 evolution under visible light(>390 nm). In these suspension systems, the efficiency of H2 evolution is strongly influenced by the dye-sensitizers, a ruthenium complex, (n-Bu4N)2-cis-Ru(dcbpy)(SCN)2] (N719, dcbpy=4,4'-dicarboxy-2,2'-bipyridine) and porphyrin derivatives 5,10,15,20-tetra(4-carboxyphenyl)porphyrin(TCPP) and tetra-(p-sulfonato phenyl) porphyrin(TPPS), and the combination with co-existing electron donor species, methanol(MeOH) and triethanolamine(TEOA). The analysis of fluorescence quenching and photoelectrochemical studies reveal that the charge transfer between the excited dye-sensitizers and TiO2 is strongly influenced by the surroundings, especially the concentration of co-existing donor species rather than the pH values of the surrounding solution. It is benefit for achieving higher conversion efficiency for not only the photocatalysts but also the photovoltaics using dye-sensitized of TiO2 nanoparticles.