Effects of Cocatalyst on Carrier Dynamics of a Titanate Photocatalyst with Layered Perovskite Structure
Effects of Cocatalyst on Carrier Dynamics of a Titanate Photocatalyst with Layered Perovskite Structure
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DOI：
10.1021/jp502775y
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发表时间：
2014-05
影响因子：
3.7
通讯作者：
Mitsunori Yabuta;Tomoaki Takayama;K. Shirai;Kazuya Watanabe;A. Kudo;T. Sugimoto;Y. Matsumoto
中科院分区：
文献类型：
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作者：
Mitsunori Yabuta;Tomoaki Takayama;K. Shirai;Kazuya Watanabe;A. Kudo;T. Sugimoto;Y. Matsumoto
在多相光催化剂分解水的过程中，通常需要添加助催化剂来提高光转化效率。在这里，我们表明，NiOx（0 < x < 1）纳米粒子负载在层状钙钛矿，BaLa 4 Ti4 O 15（BLT），作为一个有效的电子阱。用266 nm飞秒激光脉冲激发BLT，测量了BLT在空气和水中400 nm ~ 4 μm宽波长范围内的瞬态吸收（TA）时间曲线。4 μm处的TA表明光生电子在1 ps内迅速转移到助催化剂上。在402 nm处，表面光空穴对TA的时间贡献从亚μs到10 ms，受助催化剂负载量和与水的氧化还原反应的影响。TA在402 nm处的衰减曲线与陷阱-脱陷阱动力学模型的拟合表明，水的氧化明显开始于泵脉冲后约1 ms处，而水的还原发生在氧化之前的早期时域中。这个小恶魔...
Cocatalysts are usually needed to improve photoconversion efficiency in water splitting with heterogeneous photocatalysts. Here, we show that NiOx (0 < x < 1) nanoparticles loaded on a layered perovskite, BaLa4Ti4O15 (BLT), serve as an effective electron sink. We have measured the time profiles of transient absorption (TA) of BLT with and without loading NiOx cocatalyst in air and in water in a wide wavelength range from 400 nm to 4 μm upon excitation with a femtosecond pulse at 266 nm. TA at 4 μm indicates that photogenerated electrons are rapidly transferred to cocatalyst within 1 ps. The time profile of TA at 402 nm from sub-μs to 10 ms contributed by surface photoholes is affected by loading of cocatalyst and redox reactions with water. Fittings of the decay profiles of TA at 402 nm with a trap–detrap kinetic model indicate that the oxidation of water appreciably starts at around 1 ms after the pump pulse, while the reduction of water takes place prior to oxidation in much early time domains. This imp...