催化学报

催化学报 ›› 2019, Vol. 40 ›› Issue (5): 620-630.DOI: 10.1016/S1872-2067(19)63279-1

• 论文 • 上一篇    下一篇

人工氧缺陷对提高Bi2O2CO3纳米片光催化活性和选择性的关键作用

红婧a, 陈鹏c, 袁小亚d, 张育新e, 黄洪伟f, 王里奥a, 董帆b   

  1. a 重庆大学煤矿灾害动力学与控制国家重点实验室, 资源及环境科学学院, 重庆 400044;
    b 电子科技大学基础与前沿科学研究院, 环境科学与技术研究中心, 四川成都 611731;
    c 重庆工商大学环境与资源学院, 催化与环境新材料重庆市重点实验室, 重庆 400067;
    d 重庆交通大学材料科学与工程学院, 重庆 400074;
    e 重庆大学材料科学与工程学院, 机械传动国家重点实验室, 重庆 400044;
    f 中国地质大学材料科学与工程学院, 矿物岩石材料开发应用国家专业实验室, 北京 100083
  • 收稿日期:2018-12-12 修回日期:2018-12-14 出版日期:2019-05-18 发布日期:2019-03-30
  • 通讯作者: 董帆
  • 基金资助:

    国家重点研发计划（2016YFC02047）；国家自然科学基金（21822601，21777011，21501016）；重庆市研究生创新基金（CYS18019）；重庆市高校创新团队（CXTDG201602014）；重庆市自然科学基金（cstc2017jcyjBX0052）；国家“万人计划”青年拔尖人才项目.

Pivotal roles of artificial oxygen vacancies in enhancing photocatalytic activity and selectivity on Bi2O2CO3 nanosheets

Hongjing Liua, Peng Chenc, Xiaoya Yuand, Yuxin Zhange, Hongwei Huangf, Li'ao Wanga, Fan Dongb   

  1. a State Kay Laboratory of Coal Mine Disaster Dynamics and Control, College of Resource and Environmental Science, Chongqing University, Chongqing 400044, China;
    b Research Center for Environmental Science & Technology, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, Sichuan, China;
    c Chongqing Key Laboratory of Catalysis and New Environmental Materials, College of Environment and Resources, Chongqing Technology and Business University, Chongqing 400067, China;
    d College of Materials Science and Engineering, Chongqing Jiaotong University, Chongqing 400074, China;
    e State Key Laboratory of Mechanical Transmissions, College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
    f National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
  • Received:2018-12-12 Revised:2018-12-14 Online:2019-05-18 Published:2019-03-30
  • Contact: S1872-2067(19)63279-1
  • Supported by:

    This work was supported by the National Key R&D Program of China (2016YFC02047), the National Natural Science Foundation of China (21822601, 21777011, and 21501016), the Graduate Research and Innovation Foundation of Chongqing (CYS18019), the Innovative Research Team of Chongqing (CXTDG201602014), the Natural Science Foundation of Chongqing (cstc2017jcyjBX0052), and the National Special Supporting National Plan for High-Level. The authors also acknowledge the AM-HPC in Suzhou, China for computational support.

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摘要：

碳酸氧铋（Bi2O2CO3，BOC）是一种新兴的半导体光催化剂.然而，纯BOC具有较强的紫外光吸收能力和较高的载流子复合率，因而其光催化效率较低.本研究通过添加NaBH4在BOC表面引入氧缺陷（标记为OV-BOC），以拓宽光吸收范围，提高电荷分离效率.结果表明，NaBH4的加入改变了BOC的表面结构，产生了更多的氧缺陷作为活化反应物的反应位点，使光催化净化NO的去除率由BOC的10.0%提高到OV-BOC的50.2%.XRD、XPS和EPR的测定结果证明了含有氧缺陷的正方晶系BOC的成功合成.SEM和TEM表征发现OV-BOC为纳米片状结构，并且其表面的确因缺陷而形成了晶格条纹的变化.UV-vis DRS、Mott-Schottky和禁带宽度计算结果发现BOC中的氧缺陷可以减小禁带宽度，而PL和SPV的测定结果表明氧缺陷也促进了电荷转移.根据ESR谱和DFT计算结果，OV-BOC的所有活性氧信号强度大大超过BOC，进一步证明氧缺陷可以促进载流子的生成和运输.此外，OV-BOC的·OH信号强度超过BOC，说明氧缺陷可以驱动电子/空穴的分离，从而促进·OH的产生.因此，O2和H2O分子的活化被促进，从而产生更多的活性氧参与光催化反应并极大地提高了NO的去除效率.另外，利用原位红外光谱动态监测了光催化氧化NO反应的中间产物的演化过程.结合原位红外光谱和DFT的结果表明，氧缺陷能促进OV-BOC中间产物和表面氧缺陷之间的电子交换，使反应物更容易被活性自由基氧化，这有利于NO转化为目标产物从而抑制毒副产物的生成.该研究为提高光催化剂活性和选择性提供了新的途径，也为理解气相光催化反应机理提供了新的思路.

关键词: 碳酸氧铋, 氧缺陷, 可见光催化, 反应物活化, 光催化机理

Abstract:

There is an increasing interest in bismuth carbonate (Bi2O2CO3, BOC) as a semiconductor photocatalyst. However, pure BOC strongly absorbs ultraviolet light, which drives a high recombination rate of charge carriers and thereby limits the overall photocatalysis efficiency. In this work, artificial oxygen vacancies (OV) were introduced into BOC (OV-BOC) to broaden the optical absorption range, increase the charge separation efficiency, and activate the reactants. The photocatalytic removal ratio of NO was increased significantly from 10.0% for pure BOC to 50.2% for OV-BOC because of the multiple roles played by the oxygen vacancies. These results imply that oxygen vacancies can facilitate the electron exchange between intermediates and the surface oxygen vacancies in OV-BOC, making them more easily destroyed by active radicals. In situ DRIFTS spectra in combination with electron spin resonance spectra and density functional theory calculations enabled unraveling of the conversion pathway for the photocatalytic NO oxidation on OV-BOC. It was found that oxygen vacancies could increase the production of active radicals and promote the transformation of NO into target products instead of toxic byproducts (NO2), thus the selectivity is significantly enhanced. This work provides a new strategy for enhancing photocatalytic activity and selectivity.

Key words: Bismuth carbonate, Oxygen vacancy, Visible light photocatalysis, Reactant activation, Photocatalysis mechanism