Time-resolved infrared spectroscopy of K3Ta3B2O12 photocatalysts for water splitting
Time-resolved infrared spectroscopy of K3Ta3B2O12 photocatalysts for water splitting
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DOI：
10.1021/jp057536x
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发表时间：
2006-04-20
影响因子：
3.3
通讯作者：
Onishi, H
中科院分区：
文献类型：
--
作者：
Ikeda, T;Fujiyoshi, S;Onishi, H
用微秒分辨率的时间分辨红外吸收光谱观察到了紫外光催化分解水反应的高效光催化剂K3Ta3B2O12中的光激发电子。当用266 nm光脉冲照射催化剂时，在3000-1500 cm(-1)处出现无结构吸收。吸收被指定为电子的光学跃迁，这些电子被带隙激发，然后被困在中间能隙状态。由于电子-空穴复合，吸光度随时间延迟衰减。在Ar气氛中的复合速率对催化剂制备中使用的起始原料的组成很敏感。将催化剂暴露在水蒸气中，加速了电子的衰减。加速的程度与在稳态光照射下观察到的H-2产生率定性相关。
Electrons photoexcited in K3Ta3B2O12, an efficient photocatalyst for the water-splitting reaction driven by ultraviolet light, were observed using time-resolved IR absorption spectroscopy with microsecond resolution. When the catalyst was irradiated with 266 nm light pulses, a structureless absorption appeared at 3000-1500 cm(-1). The absorption was assigned to the optical transition of electrons that were band gap-excited and then trapped in mid-gap states. The absorbance decayed with a time delay because of the electron-hole recombination. The rate of recombination in an argon atmosphere was sensitive to the composition of the starting material used in the catalyst preparation. The electron decay was accelerated by exposing the catalyst to water vapor. The degree of acceleration was qualitatively correlated with the H-2 production rate observed during steady-state light irradiation.