催化学报

催化学报 ›› 2019, Vol. 40 ›› Issue (5): 664-672.DOI: 10.1016/S1872-2067(18)63201-2

• 论文 • 上一篇    下一篇

Al修饰C2N对甲醛降解的吸附增强机理及潜在催化活性的密度泛函理论研究

苏岳檀, 李文浪, 李桂英, 敖志敏, 安太成   

  1. 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, 广州市环境催化及污染控制重点实验室, 广东广州 510006
  • 收稿日期:2018-10-21 修回日期:2018-11-17 出版日期:2019-05-18 发布日期:2019-03-30
  • 通讯作者: 敖志敏
  • 基金资助:

    国家自然科学基金目（21607029，21777033，41373102）；广东省科技计划（2017B020216003）；广州市科技计划（201707010359）；广东省教育厅创新团队项目（2017KCXTD012）；国家“千人计划”青年项目.

Density functional theory investigation of the enhanced adsorption mechanism and potential catalytic activity for formaldehyde degradation on Al-decorated C2N monolayer

Yuetan Su, Wenlang Li, Guiying Li, Zhimin Ao, Taicheng An   

  1. Guangzhou Key Laboratory of 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
  • Received:2018-10-21 Revised:2018-11-17 Online:2019-05-18 Published:2019-03-30
  • Contact: 10.1016/S1872-2067(18)63201-2
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21607029, 21777033 and 41373102), the Science and Technology Program of Guangdong Province (2017B020216003), the Science and Technology Program of Guangzhou City (201707010359), the Innovation Team Project of Guangdong Provincial Department of Education (2017KCXTD012), the "1000 Plan" for Young Professionals' Program of China, and the National Supercomputing Centre in Guangzhou.

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摘要：

羰基化合物，特别是甲醛，是室内最常见的对人体有害的空气污染物之一.如何对甲醛进行有效的控制已成为当前研究热点.在本工作中，我们使用密度泛函理论化学计算方法研究了甲醛分子在C2N和Al修饰C2N上的吸附性能.结果表明，纯C2N对甲醛分子的吸附能力较弱，吸附能仅为-0.583 eV，C2N经Al原子修饰改性后，吸附能为-2.585 eV，超过了改性前的4倍，有效增强了体系对甲醛分子的吸附能力.为了研究甲醛分子在Al修饰C2N上的吸附增强机理，我们对局部态密度（PDOS）、Mulliken电荷分布及电子密度分布进行了计算.结果表明，Al原子修饰改变了附近的电子分布，从而改变了修饰Al原子的化学和物理行为，使其起到了连接甲醛分子和C2N层的桥梁作用，从而加强了吸附能力.
此外，为了研究产生对甲醛活化有效的羟基自由基（·OH）和超氧（O2·-）自由基的可能，我们还计算了C2N结构对H2O分子和O2分子的吸附.结果表明，Al修饰的C2N对H2O分子和O2分子同样有很强的吸附能力.对于H2O分子，在纯C2N结构中的吸附能为-0.743 eV，在Al原子修饰后的结构中，其吸附能高达-3.177 eV，并且此时H2O分子能够自发解离成一个羟基和一个H原子，其中羟基与修饰的Al原子相连，这为羟基自由基的生成提供了良好的条件.而对于O2分子，在纯C2N结构中的吸附能仅为-0.206 eV，在Al原子修饰后其吸附能高达-2.767 eV，约为修饰前的13倍，这使得化学吸附的O2分子也具有更高的获得额外电子和高电位被激活为超氧自由基的潜能，这也为超氧自由基的生成提供了良好基础.上述研究表明，Al修饰C2N是一种有前途的材料，可用于甲醛分子的吸附及催化降解.

关键词: C2N, 密度泛函理论, 二维材料, 甲醛, 吸附, 催化降解

Abstract:

Carbonyl compounds, in particular formaldehyde (HCHO), are among the most common indoor air pollutants that have been found to be toxic to humans. Thus, in this study, density functional theory (DFT) calculations are performed to study the adsorption properties of HCHO on pristine and Al-decorated C2N monolayer. The results indicate that Al-decorated C2N has a strong adsorption ability for HCHO molecules with an adsorption energy of -2.585 eV. Moreover, partial density of states (PDOS), Mulliken atomic charges, and electron density distributions are calculated to investigate the adsorption enhancement mechanism. The results show that the Al atom serves as a bridge to connect the adsorbed molecules and the C2N monolayer, thus strengthening the adsorption. Furthermore, we study the adsorption of H2O and O2 with the possible generation of hydroxyl (·OH) and superoxide (O2·-) radicals, which are active for HCHO degradation; the results show that both molecules can also be strongly adsorbed on the Al-decorated C2N surface. In particular, the dissociation of H2O provides an excellent precondition for the generation of hydroxyl radicals. Our findings suggest that Al-decorated C2N can be a promising material for the adsorption and subsequent catalytic degradation of HCHO molecules.

Key words: C2N, Density functional theory, Two-dimensional material, Formaldehyde, Adsorption, Catalytic degradation