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基于等离激元热电子调控的全谱光催化产氢增强(英文)
引用本文:李燕瑞,郭宇,龙冉,刘东,赵大明,谭余波,高超,沈少华,熊宇杰.基于等离激元热电子调控的全谱光催化产氢增强(英文)[J].催化学报,2018,39(3):453-462.
作者姓名:李燕瑞  郭宇  龙冉  刘东  赵大明  谭余波  高超  沈少华  熊宇杰
作者单位:西安交通大学, 动力工程多相流国家重点实验室,国际可再生能源研究中心, 陕西西安710049 中国科学技术大学, 化学与材料科学学院, 能源材料化学协同创新中心, 合肥微尺度物质科学国家实验室, 安徽合肥230026
基金项目:国家重点研发计划专项项目,国家重点基础研究发展计划,国家自然科学基金,中国科学院前沿科学重点研究项目,中国科学院创新交叉团队;合肥物质科学技术中心方向项目,国家千人计划,中科院百人计划,安徽省自然科学基金,中国博士后科学基金,中央高校基本科研业务费专项资金,This work was supported in part by the National Key Research&Development Program of China,the National Basic research and Development Program of China,the National Natural Science Foundation of China,CAS Key Research Program of Frontier Sciences,CAS Interdisciplinary Innovation Team;Anhui Provincial Natural Science Foundation,China Postdoctoral Science Foundation,Fundamental Research Funds for the Central Universities
摘    要:等离激元效应在光催化体系中的集成为实现广谱光吸收提供了一个新的途径,然而等离激元热电子的较低迁移率和不确定扩散方向使得其光催化效率仍较低.等离激元金属与n型半导体接触后,其界面间会形成肖特基结.在特定波长太阳光照射下,等离激元金属将其表面等离子体能量聚集在表面自由电子上,进而产生热电子.当这些热电子具有的能量高于肖特基势垒时,热电子便可注入到半导体导带上.与此同时,半导体上的电子可以通过肖特基接触发生回流,与金属上的空穴复合,进而降低半导体-等离激元金属复合材料的光催化性能.因此,为了提高光催化效率,如何调控等离激元热电子迁移和充分利用等离激元效应是一个重要挑战.本文尝试将"表面异质结"与肖特基结相结合的复合结构,得以有效地调控等离激元热电子的迁移.在该复合结构中,金纳米颗粒和铂纳米颗粒分别作为等离激元吸光单元和助催化剂,集成在TiO_2纳米片表面.其中"表面异质结"是由TiO_2纳米片的两种不同表面晶面所构成,我们选择由{001}和{101}两组晶面组成的TiO_2纳米片作为半导体衬底.该结构中的{001}晶面导带能级高于{101}导带能级,因而电子由高能级的{001}流向低能级的{101}晶面,可以用来引导等离激元热电子从可见光响应的金纳米颗粒向TiO_2进行高效转移.通过巯基丙酸的桥联作用,将等离激元Au纳米颗粒锚定在TiO_2纳米片的{001}晶面上,获得Au-TiO_2{001}样品.另一方面,利用TiO_2纳米片自身光生电荷导向性光沉积,得到与{101}晶面结合形成的Au-TiO_2{101}样品.我们对两组样品进行光电流和光催化产氢实验对比,确认在"表面异质结"诱导下Au-TiO_2{001}样品中Au产生的光生热电子可以更好地注入到TiO_2纳米片导带上.我们进一步通过光沉积Pt纳米颗粒来判定光生电子所能到达的区域,验证了以上结论.与此同时,肖特基结由铂纳米颗粒与TiO_2纳米片所形成,可以促使电子由TiO_2向铂纳米颗粒进行转移,而避免发生向金纳米颗粒的反向迁移,从而在Au-TiO_2体系中实现高效的单向载流子转移.基于该设计,等离激元光催化剂实现了明显改善的全谱光催化产氢性能.本文为全谱光催化的复合结构理性设计提供了一个新的思路.

关 键 词:等离激元  表面异质结  肖特基结  光催化产氢  全谱光照  Plasmonics  Surface  heterojunction  Schottky  junction  Photocatalytic  hydrogen  production  Full  spectrum
收稿时间:26 September 2017

Steering plasmonic hot electrons to realize enhanced full-spectrum photocatalytic hydrogen evolution
Yanrui Li,Yu Guo,Ran Long,Dong Liu,Daming Zhao,Yubo Tan,Chao Gao,Shaohua Shen,Yujie Xiong.Steering plasmonic hot electrons to realize enhanced full-spectrum photocatalytic hydrogen evolution[J].Chinese Journal of Catalysis,2018,39(3):453-462.
Authors:Yanrui Li  Yu Guo  Ran Long  Dong Liu  Daming Zhao  Yubo Tan  Chao Gao  Shaohua Shen  Yujie Xiong
Institution:1. International Research Centre for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi''an Jiaotong University, Xi''an 710049, Shaanxi, China;2. Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, Anhui, China
Abstract:Integration of surface plasmons into photocatalysis is an intriguing approach to extend the light absorption range over the full solar spectrum. However, the low migration rates and uncertain diffusion directions of plasmonic hot electrons make their photocatalytic efficiency fail to meet expectations. It remains a challenging task to steer the migration of hot electrons and take full ad-vantage of the plasmonic effect to achieve the desired high photocatalytic efficiency. Herein, we have developed an efficient strategy to steer the migration of plasmonic hot electrons through a well-designed hybrid structure that synergizes a "surface heterojunction" with a Schottky junction. The hybrid structure was synthesized by modifying titanium dioxide (TiO2) nanosheets (NSs) with gold (Au) nanoparticles (NPs) as a plasmonic metal and platinum (Pt) NPs as a co-catalyst. The"surface heterojunction" formed between two different crystal facets in the TiO2 NSs can induce the injection of plasmonic hot electrons from Au NPs excited by visible light to TiO2. Meanwhile, the Schottky junction formed between the Pt NPs and TiO2 NSs can force the migration of electrons from TiO2 to Pt NPs instead of flowing to Au NPs, attaining the efficient unidirectional transfer of carriers in the Au-TiO2 system. Plasmonic photocatalysts with this design achieved dramatically enhanced activity in full-spectrum photocatalytic hydrogen production. This work opens a new window to rationally design hybrid structures for full-spectrum photocatalysis.
Keywords:Plasmonics  Surface heterojunction  Schottky junction  Photocatalytic hydrogen production  Full spectrum
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