王芳,卫诗倩,蒋帅虎,赵丰贵,周莹.层状Bi2O2CO3可见光催化活性增强机理研究[J].稀有金属材料与工程,2019,48(7):2225~2231.[wangfang,Wei Shiqian,Jiang Shuaihu,Zhao Fenggui,Zhou Ying.Enhanced mechanism study of visible-light photocatalytic activity of Bi2O2CO3[J].Rare Metal Materials and Engineering,2019,48(7):2225~2231.]
层状Bi2O2CO3可见光催化活性增强机理研究
投稿时间:2018-02-04  修订日期:2018-02-28
中文关键词:  Bi2O2CO3  氧缺陷  密度泛函理论
基金项目:四川省青年科技创新研究团队(批准号:2016TD0011);四川省国际合作项目(批准号:2017HH0030)
中文摘要:
      本文基于第一性原理方法,研究Bi2O22+和CO32-交替层中氧缺陷生成对晶体结构、能带结构以及光学性质的影响,揭示氧缺陷提高Bi2O2CO3可见光催化活性作用机制。计算结果发现,氧缺陷的存在对Bi2O2CO3的晶胞参数和Bi-O键影响较小,但作为电子施主中心可以向周围原子提供电子,造成Bi2O2CO3电荷分布发生变化,有效减小能带间隙,促进Bi2O2CO3对可见光的吸收,且这种现象随着氧缺陷浓度的升高更加明显。值得注意的是,Bi2O22+层和CO32-层氧缺陷的作用不同。CO32-层中氧缺陷的形成导致费米能级附近出现缺陷能级,改变了电子的跃迁方式。相较于CO32-层,氧缺陷更容易存在于Bi2O22+层中,能够更佳有效地减小Bi2O2CO3的能带间隙,进一步促进Bi2O2CO3对可见光的吸收。随着Bi2O22+和CO32-层氧缺陷浓度增加,Bi2O22+层氧缺陷的作用愈明显,当浓度达到6.25%时,Bi2O2CO3在可见光区的响应显著增强,有利于提高Bi2O2CO3可见光催化活性。本文计算结果解释了实验上氧缺陷增强Bi2O2CO3光催化活性现象,并为今后合成其它含氧缺陷Bi基金属氧化物提供理论指导。
Enhanced mechanism study of visible-light photocatalytic activity of Bi2O2CO3
英文关键词:Bismuth subcarbonate, oxygen vacancy, density functional theory
英文摘要:
      This work studied the effect of oxygen vacancies in the Bi2O22+ and CO32- layers on the crystal structures, electronic and optical properties of Bi2O2CO3 with density functional theory (DFT) methods. The cell parameters and Bi-O bond lengths of Bi2O2CO3 before and after the introduction of oxygen vacancies were similar, so the effect of oxygen vacancies on crystal structures could be ignored. However, oxygen vacancies as electron doner provided electrons for the surrounding atoms, resulting in the change of charge distributions after the introduction of oxygen vacancies. Moreover, oxygen vacancies could reduce the band gap of Bi2O2CO3 and enhance the adsorption of visible light. This effect of oxygen vacancies became more obvious with the increasing of oxygen vacancy concentration. It was notable that the effects of oxygen vacancies in the Bi2O22+ and CO32- layers were different. Once a oxygen vacancy was introduced in the CO32- layer, a defect level appeared within the band gap of Bi2O2CO3. The oxygen vacancies in the Bi2O22+ layer were more easily formed in Bi2O2CO3 than that in the CO32- layer. Further more, the functions of oxygen vacancies in the Bi2O22+ layer for the reduction of band gap and the enhancement of visible light adsorption were more effective than that the oxygen vacancies in the CO32- layer, which was more obvious with the increasing of oxygen vacancy concentration. When the concentration of oxygen vacancies in the Bi2O22+ layer reached to 6.25%, the photoelectric properties of Bi2O2CO3 were the best. The DFT calculation results are consistent with the previous experimental results, and could provide insights into the mechanism for promoting the photoelectric properties of Bi2O2CO3 and other bismuth-based materials.
作者单位E-mail
王芳 西南石油大学 wangfnjust@163.com 
卫诗倩 西南石油大学 weisq_swpu@163.com 
蒋帅虎 西南石油大学  
赵丰贵 西南石油大学  
周莹 西南石油大学  
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