催化学报

催化学报 ›› 2019, Vol. 40 ›› Issue (5): 755-764.DOI: 10.1016/S1872-2067(19)63320-6

• 论文 • 上一篇    下一篇

利用Bi的SPR效应增强Bi2WO6的可见光催化NO氧化去除性能

张荔a, 杨超a, 吕康乐a, 陆亚超a, 李覃a, 伍晓锋a, 李宇涵b, 黎小芳c, 范佳杰d, 李玫a   

  1. a 中南民族大学资源与环境学院, 催化材料科学湖北省重点实验室, 湖北武汉 430074;
    b 重庆工商大学废油回收技术与装备工程研究中心, 重庆市催化与新环境材料重点实验室, 重庆 400067;
    c 武汉科技大学化学化工学院, 湖北武汉 430081;
    d 郑州大学材料科学与工程学院, 河南郑州 450001
  • 收稿日期:2019-01-03 修回日期:2019-01-29 出版日期:2019-05-18 发布日期:2019-03-30
  • 通讯作者: 吕康乐, 李玫
  • 基金资助:

    国家自然科学基金（51672312，21373275，51808080和21571192）；中南民族大学中央高校基本科研业务费专项资金资助（CZT19006）重庆市基础研究与前沿探索项目（cstc2018jcyjA3794）；中国“博士后创新人才支持计划”项目（BX20180056）和中国博士后科学基金（2018M643788XB）.

SPR effect of bismuth enhanced visible photoreactivity of Bi2WO6 for NO abatement

Li Zhanga, Chao Yanga, Kangle Lva, Yachao Lua, Qin Lia, Xiaofeng Wua, Yuhan Lib, Xiaofang Lic, Jiajie Fand, Mei Lia   

  1. a Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission & Ministry of Education, Hubei Province, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074, Hubei, China;
    b Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China;
    c College of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China;
    d School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China
  • Received:2019-01-03 Revised:2019-01-29 Online:2019-05-18 Published:2019-03-30
  • Contact: S1872-2067(19)63320-6
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (51672312, 21373275, 51808080, 21571192), the Fundamental Research Funds for the Central Univsrsity, South-Central University for Nationalities (CZT19006), the Natural Science Foundation Project of CQ CSTC (cstc2018jcyjA3794), China "post-doctoral innovative talent support program" (BX20180056), and China Postdoctoral Science Foundation (2018M643788XB).

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摘要：

作为大气中的典型污染物之一，化石燃料燃烧产生的NO不仅会引起酸雨，还会影响人体呼吸系统.半导体光催化技术可以利用太阳能和空气中的氧气来分解环境污染物，因而得到了国内外学者的广泛关注.作为最具代表性的半导体光催化材料，TiO2虽然具有较强的氧化能力和优异的生物相容性，但是其禁带宽度较大（3.2 eV）而只能被紫外光激发，无法充分利用太阳能.因此，开发新型可见光响应的半导体催化材料具有重要意义.Bi2WO6是一种独特的具有层状结构半导体光催化材料，因其具有可见光响应性能而受到了广泛关注；但是可见光响应范围窄（禁带宽度2.6-2.8 eV）以及其较快的光生载流子复合，导致Bi2WO6其光催化效率不高，迫切需要采取有效措施对Bi2WO6进行改性.
贵金属（诸如金和银）纳米粒子可见光区的表面等离子体效应（SPR），可以用来增强半导体材料的可见光催化性能.但是，贵金属的价格昂贵，难以满足实际需求.近来的研究发现，非贵金属Bi同样具有类似的表面等离子体效应.因此，本文选用以乙二醇为还原剂，通过低温还原Bi （NO3）3的方式，在花球Bi2WO6表面，成功制备了沉积了Bi纳米球复合光催化次材料.本文用NO的可见光催化氧化来评价Bi/Bi2WO6复合材料的光催化性能的可见光催化性能，所使用的光源为可见光LED灯（λ > 400 nm）.结果发现：（1）单一组分的Bi金属和Bi2WO6前驱体花球均表现出非常差的光催化活性，NO去除率分别仅为7.7%和8.6%；（2）随着Bi纳米球的负载量从0增加至10 wt%，复合材料Bi/Bi2WO6的NO去除效率从12.3%稳定增加至53.1%至20 wt%时开始降低.这可能是由于Bi纳米球阻碍了Bi2WO6对光的吸收；（3）改性后的Bi/Bi2WO6具有良好的可见光催化稳定性，循环使用在五次后其活性变化不大.
光催化机理研究结果显示，Bi/Bi2WO6增强的可见光NO去除性能归因于Bi纳米球的SPR效应.在可见光照射下，Bi纳米球的SPR效应产生的电场可以显著促进Bi2WO6的光生载流子分离效率.同时，Bi纳米球可以快速转移Bi2WO6导带上的光生电子，生成超氧游离基（·O2-），从而抑制了光生电子和空穴的复合.Bi2WO6表面的空穴可以被表面吸附水捕获，产生羟基自由基（·OH）.在活性氧物种·OH和·O2-的不断进攻作用下，NO最终被氧化.本文为宽禁带半导体的非贵金属敏化，提升其可见光催化性能解决环境问题提供了新思路.

关键词: 铋, Bi2WO6, 表面等离子体, 光催化, 氧化氮

Abstract:

Bi2WO6 is a typical visible-light-responsive semiconductor photocatalyst with a layered structure. However, the relatively large bandgap (2.6-2.8 eV) and quick recombination of photo-generated carriers result in its low quantum efficiency. In this paper, Bi-nanospheres-modified flower-like Bi2WO6 was successfully prepared by solvothermal treatment of Bi2WO6 powders in Bi(NO3)3 solution using ethylene glycol as reductant. The photoreactivity of this photocatalyst was evaluated by the oxidation of NO in a continuous-flow reactor under irradiation by a visible LED lamp (λ > 400 nm). It was found that both Bi nanospheres and flower-like Bi2WO6 precursor exhibit very poor photocatalytic activity with NO removal rates of only 7.7% and 8.6%, respectively. The photoreactivity of Bi/Bi2WO6 was found to steadily increase from 12.3% to 53.1% with increase in the amount of Bi nanospheres from 0 to 10 wt%. However, with further increase in the loading amount of Bi nanospheres, the photoreactivity of Bi/Bi2WO6 hybridized photocatalyst begins to decrease, possibly due to the light filtering by the Bi nanospheres. The enhanced visible photoreactivity of Bi/Bi2WO6 towards NO abatement was attributed to surface plasmon resonance driven interfacial charge separation. The excellent stability of Bi/Bi2WO6 hybridized photocatalyst towards NO oxidation demonstrates its potential for applications such as air purification.

Key words: Bismuth, Bi2WO6, Surface plasmon resonance, Photocatalysis, NO