催化学报 ›› 2017, Vol. 38 ›› Issue (7): 1174-1183.DOI: 10.1016/S1872-2067(17)62849-3

• 论文 • 上一篇    下一篇

Bi-O-Si键作为热电子传输通道增强SiO2@Bi微球的等离子体光催化效率

倪紫琳a, 张文东b, 蒋光明a, 王小平a, 鲁贞贞c, 孙艳娟a, 李欣蔚a, 张育新d, 董帆a   

  1. a 重庆工商大学环境与资源学院, 重庆市催化与环境新材料重点实验室, 教育部废油资源化技术与设备工程研究中心, 重庆 400067;
    b 重庆师范大学科研处, 重庆 401331;
    c 重庆交通大学土木工程学院, 重庆 400074;
    d 重庆大学材料科学与工程学院, 重庆 400044
  • 出版日期:2017-07-18 发布日期:2017-06-27
  • 通讯作者: 孙艳娟, 董帆
  • 基金资助:

    国家自然科学基金(21501016,51478070,21406022,21676037);国家重点研发计划(2016YFC0204702);重庆市高校创新团队建设计划(CXTDG201602014);重庆市自然科学基金(cstc2016jcyjA0481,cstc2015jcyjA0061);重庆市教委科技项目(KJ1600625,KJ1500637);交通运输部应用和基础科学项目(2015319814100);重庆工商大学创新型科研项目(yjscxx2016-060-36).

Enhanced plasmonic photocatalysis by SiO2@Bi microspheres with hot-electron transportation channels via Bi-O-Si linkages

Zilin Nia, Wendong Zhangb, Guangming Jianga, Xiaoping Wanga, Zhenzhen Luc, Yanjuan Suna, Xinwei Lia, Yuxin Zhangd, Fan Donga   

  1. a Chongqing Key Laboratory of Catalysis and New Environmental Materials, Engineering Research Center for Waste Oil Recovery Technology and Equipment of Ministry of Education, College of Environment and Resources, Chongqing Technology and Business University, Chongqing 400067, China;
    b Department of Scientific Research Management, Chongqing Normal University, Chongqing 401331, China;
    c College of Civil Engineering, Chongqing JiaoTong University, Chongqing 400074, China;
    d College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
  • Online:2017-07-18 Published:2017-06-27
  • Contact: 10.1016/S1872-2067(17)62849-3
  • Supported by:

    This work is supported by the National Natural Science Foundation of China (21501016, 51478070, 21406022, 21676037), the National Key R&D Project (2016YFC0204702), the Innovative Research Team of Chongqing (CXTDG201602014), the Natural Science Foundation of Chongqing (cstc2016jcyjA0481, cstc2015jcyjA0061), the Science and Technology Project of Chongqing Education Commission (KJ1600625, KJ1500637), the Application and Basic Science Project of Ministry of Transport of People's Republic of China (2015319814100), and the Innovative Research Project from CTBU (yjscxx2016-060-36).

摘要:

具有等离子体效应的贵金属Au和Ag等常被用于修饰半导体光催化剂.非贵金属Bi成本低,来源丰富,最近被报道可以直接作为等离子体光催化剂应用于空气中NO净化.为了进一步提高Bi单质的光催化活性,需对其进行改性.SiO2的禁带宽度过大,不能单独作为光催化剂,但它的稳定性好,比表面积大,因而常作复合材料用于提高光催化剂的反应效率、稳定性及对反应物的吸附能力.目前,尚未见SiO2修饰Bi单质的相关报道.
本文通过溶剂热法制备了SiO2@Bi微球,并对其微结构进行了表征,对光催化氧化NO的反应过程进行了原位漫反射红外光谱(DRIFTS)分析,揭示了Bi-O-Si键在提升SiO2@Bi光催化氧化NO性能中的作用机制.结果显示,用SiO2纳米颗粒修饰Bi球,形成的Bi-O-Si键作为热电子传输通道,能显著提高Bi单质光催化氧化去除NO的能力.
扫描电镜、透射电镜、傅里叶变换红外光谱和X射线光电子能谱等表征结果表明,SiO2纳米颗粒负载于Bi球上,且SiO2@Bi内形成了Bi-O-Si键.作为光生热电子的传输通道,Bi-O-Si键能促进光生电子的转移和载流子的分离,提高活性自由基·OH和·O2-的产量,增强SiO2@Bi在紫外光下等离子体光催化氧化NO的能力.自由基捕获测试(ESR)表明,SiO2@Bi在光催化反应中产生的·OH和·O2-数量均明显高于单质Bi在反应中形成自由基的数量.原位DRIFTS发现,Bi-O-Si键能快速转移光生电子,从而有利于NO → NO2 → NO3-反应的进行.此外,SiO2@Bi的比表面积变大,因而对NO的吸附能力增强,同时促进了光催化反应.本文揭示了SiO2@Bi等离子体光催化性能增强的微观机制和光催化氧化NO的反应机理,为Bi基光催化剂的改性和应用提供了新的认识.

关键词: SiO2@Bi金属, Bi-O-Si键, 电子传输, 原位漫反射红外光谱, 光催化去除一氧化氮

Abstract:

The semimetal Bi has received increasing interest as an alternative to noble metals for use in plas-monic photocatalysis. To enhance the photocatalytic efficiency of metallic Bi, Bi microspheres modi-fied by SiO2 nanoparticles were fabricated by a facile method. Bi-O-Si bonds were formed between Bi and SiO2, and acted as a transportation channel for hot electrons. The SiO2@Bi microspheres exhibited an enhanced plasmon-mediated photocatalytic activity for the removal of NO in air under 280 nm light irradiation, as a result of the enlarged specific surface areas and the promotion of elec-tron transfer via the Bi-O-Si bonds. The reaction mechanism of photocatalytic oxidation of NO by SiO2@Bi was revealed with electron spin resonance and in situ diffuse reflectance infrared Fourier transform spectroscopy experiments, and involved the chain reaction NO → NO2 → NO3- with ·OH and ·O2- radicals as the main reactive species. The present work could provide new insights into the in-depth mechanistic understanding of Bi plasmonic photocatalysis and the design of high-performance Bi-based photocatalysts.

Key words: SiO2@Bi metal, Bi-O-Si bond, Electron transfer, In situ diffuse reflectance infrared Fourier transform spectroscopy, Photocatalytic nitric oxide removal