Anomalous Photoinduced Hole Transport in Type I Core/Mesoporous-Shell Nanocrystals for Efficient Photocatalytic H2 Evolution
Anomalous Photoinduced Hole Transport in Type I Core/Mesoporous-Shell Nanocrystals for Efficient Photocatalytic H2 Evolution
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DOI：
10.1021/acsnano.9b03826
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发表时间：
2019-07-01
期刊：
影响因子：
17.1
通讯作者：
Teranishi, Toshiharu
中科院分区：
文献类型：
--
作者：
Lian, Zichao;Sakamoto, Masanori;Teranishi, Toshiharu
控制半导体纳米颗粒光催化剂中的载体动力学是开发催化活性的关键。通常，I型能带排列不适合光催化剂，因为光生载流子在窄带隙半导体中积累。为了避免由载流子积累引起的反应终止和/或材料的光腐蚀，通常采用用于光能转换系统的II型能带对准而不是I型。然而，CdS/ZnS核/介孔壳异质结构显示出上级光催化活性，尽管具有I型能带排列，这通常不利于光催化反应。瞬态吸收光谱和时间分辨的微波电导率揭示了有效的光致空穴转移从CdS相到ZnS相。从CdS到ZnS相的缺陷介导的空穴转移导致长寿命的电荷分离（> 2.4ms），从而导致高的光催化性能。本研究提供了深入了解缺陷介导的纳米颗粒光催化剂中的载体转移，这可以作为一个指导方针，设计高活性和稳定的纳米颗粒光催化剂。
Controlling the carrier dynamics in a semiconductor nanoparticulate photocatalyst is the key to developing catalytic activity. Generally, type I band alignment is unsuitable for photocatalysts because the photoinduced carriers accumulate in the narrow bandgap semiconductor. To avoid the termination of reactions and/or photocorrosion of materials caused by carrier accumulation, it is common to employ type II band alignment for photoenergy conversion systems instead of type I. However, CdS/ZnS core/mesoporous-shell heterostructures show superior photocatalytic activity despite having type I band alignment that is generally unfavorable for photocatalytic reactions. Transient absorption spectroscopy and time-resolved microwave conductivity revealed efficient photoinduced hole transfer from the CdS phase to the ZnS phase. The defect-mediated hole transfer from the CdS to the ZnS phase resulted in long-lived charge separation (>2.4 ms) leading to high photocatalytic performance. This study provides insight into defect-mediated carrier transfer in nanoparticulate photocatalysts, which could be used as a guideline for the design of highly active and stable nanoparticulate photocatalysts.