Long-time charge separation in porphyrin/KTa(Zr)O3 as water splitting photocatalyst
Long-time charge separation in porphyrin/KTa(Zr)O3 as water splitting photocatalyst
复制标题
DOI：
10.1039/c1cp22425e
复制
发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Ishihara, Tatsumi
中科院分区：
文献类型：
--
作者：
Hagiwara, Hidehisa;Inoue, Takanori;Ishihara, Tatsumi
人工光合作用是化学家的梦想之一，而长寿命的电荷分离是实现人工光合作用的基础。在实际的光合作用中，Z 型激发利用太阳光高效地分离电荷。在这里，我们报道了 Cr-四苯基氯化卟啉 (Cr-TPPCl)/Zr 掺杂 KTaO3 (KTa(Zr)O-3) 中的光激发类似于光合作用中的 Z 方案，并且我们在室温下实现了完全的电荷分离。光伏衰变和瞬态荧光光谱测量表明，KTa(Zr)O-3 中的光激发电荷在电荷转移的几百皮秒内转移到 Cr-TPPCl 的 HOMO 上。相比之下，在 KTa(Zr)O-3 初始激发后吸收光谱变化的瞬态衰减中，在室温下观察到由 KTa(Zr)O-3 电子注入形成的 Cr-TPPCl 物质的还原态持续超过 0.5 s。形成的 Cr-TPPCl 还原态高度稳定，可通过静态 ESR 测量检测到。
Artificial photosynthesis is one of the chemists' dreams and the separation of charges with long lives is fundamental for achieving artificial photosynthesis. In actual photosynthesis, Z-scheme excitation separates electronic charge with high efficiency using solar light. Here we report that photo-excitation in Cr-tetraphenylporphyrin chroride (Cr-TPPCl)/Zr doped KTaO3 (KTa(Zr)O-3) is analogous to the Z-scheme in photosynthesis, and that we achieve complete charge separation at room temperature. Photovoltaic decay and transient fluorescence spectra measurements showed that the photo-excited charge in KTa(Zr)O-3 transferred to the HOMO of Cr-TPPCl within a few hundred pico-seconds on charge transfer. In contrast, the reduced state of the Cr-TPPCl species that was formed by the electronic injection from KTa(Zr)O-3 was observed for more than 0.5 s at room temperature in the transient decay of the absorption spectra change after the initial excitation of KTa(Zr)O-3. The formed reduced state of Cr-TPPCl was highly stable and was detected by static ESR measurements.