催化学报 ›› 2020, Vol. 41 ›› Issue (10): 1633-1644.DOI: 10.1016/S1872-2067(20)63571-9

• 论文 • 上一篇    下一篇

单原子催化剂Ti/Ti3C2O2催化氧化甲醛的密度泛函理论研究

周君慧a, 刘冠兰a, 姜全国b, 赵伟娜a, 敖志敏a, 安太成a   

  1. a 广东工业大学环境健康与污染控制研究院, 环境科学与工程学院, 广东省环境催化与健康风险控制重点实验室, 广东广州 510006;
    b 河海大学力学与材料学院, 江苏南京 211100
  • 收稿日期:2020-02-21 修回日期:2020-03-23 出版日期:2020-10-18 发布日期:2020-08-15
  • 通讯作者: 敖志敏
  • 基金资助:
    国家自然科学基金(21777033,21607029,41425015);广东省科技计划(2017B020216003);广东省教育厅创新团队项目(2017KCXTD012).

Density functional theory calculations on single atomic catalysis: Ti-decorated Ti3C2O2 monolayer (MXene) for HCHO oxidation

Junhui Zhoua, Guanlan Liua, Quanguo Jiangb, Weina Zhaoa, Zhimin Aoa, Taicheng Ana   

  1. a Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, Guangdong, China;
    b The College of Mechanics and Materials, Hohai University, Nanjing 211100, Jiangsu, China
  • Received:2020-02-21 Revised:2020-03-23 Online:2020-10-18 Published:2020-08-15
  • Supported by:
    This work was supported by National Natural Science Foundation of China (21777033, 21607029, 41425015), Science and Technology Planning Project of Guangdong Province (2017B020216003), and The Innovation Team Project of Guangdong Provincial Department of Education (2017KCXTD012).

摘要: 甲醛是一种比较常见的室内污染物,长期接触甲醛会危害人体健康.如何在低温条件下有效去除低浓度甲醛仍然是当前具有挑战性的研究课题.本文采用第一性原理计算方法研究了甲醛分子在单原子催化剂(Ti原子修饰的单层MXene-Ti3C2O2)表面上的吸附和催化氧化性能.结果表明,Ti原子在Ti3C2O2表面的结合能和扩散能分别为-8.36和1.66eV,说明Ti能够以单原子形式稳定分散在Ti3C2O2表面,而不会产生团簇现象.为了研究甲醛和氧气分子在Ti/Ti3C2O2上的吸附机理,我们计算了分波态密度(PDOS),Mulliken电荷分析以及分子轨道.结果表明,Ti原子修饰改变了Ti3C2O2表面上的电荷分布,甲醛分子和氧气分子都能接受自Ti原子处转移而来的电子成为电子受体,增强了吸附质和Ti/Ti3C2O2之间的相互作用,从而加强了吸附能力.
此外,为了研究甲醛分子在Ti/Ti3C2O2上的催化氧化机理,我们考虑了Langmuir-Hinshelwood(LH)和Eley-Rideal(ER)两种机理.结果表明,无论是从动力学还是热力学角度,ER机理是一种更为理想的催化氧化甲醛的方式,甲醛分子在已经被氧气活化的Ti/Ti3C2O2上能够自动解离成CO分子,而两个H原子则和活化的O原子形成两个*OH基团,并且释放4.05eV的热量,从而有助于克服后续反应所要跨越的能垒(1.04eV).而从*OH基团到CO分子的电荷转移不仅能够促进*OH基团的活化,而且也为下一步的水分子的形成也提供了重要作用.综上所述,甲醛可以很容易地在单原子催化剂Ti/Ti3C2O2上被氧化.综上,本文为开发高效去除甲醛的非贵金属催化剂以及扩大MXene材料应用范围提供重要指导.

关键词: 甲醛氧化, MXene, Ti/Ti3C2O2, 单原子催化剂, 非贵金属催化剂

Abstract: Formaldehyde (HCHO) is a common indoor pollutant, long-term exposure to HCHO may harm human health. Its efficient removal at mild conditions is still challenging. The catalytic oxidation of HCHO molecules on a single atomic catalyst, Ti-decorated Ti3C2O2 (Ti/Ti3C2O2) monolayer, is investigated by performing the first principles calculations in this work. It demonstrates that Ti atoms can be easily well dispersed at the form of single atom on Ti3C2O2 monolayer without aggregation. For HCHO catalytic oxidation, both Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanisms are considered. The results show that the step of HCHO dissociative adsorption on Ti/Ti3C2O2 with activated O2 can release high energy of 4.05 eV based on the ER mechanism, which can help to overcome the energy barrier (1.04 eV) of the subsequent reaction steps. The charge transfer from *OH group to CO molecule (dissociated from HCHO) not only promotes *OH group activation but also plays an important role in the H2O generation along the ER mechanism. Therefore, HCHO can be oxidized easily on Ti/Ti3C2O2 monolayer, this work could provide significant guidance to develop effective non-noble metal catalysts for HCHO oxidation and broaden the applications of MXene-based materials.

Key words: Formaldehyde oxidation, MXene, Ti/Ti3C2O2 monolayer, Single atomic catalysts, Non-noble metal catalyst