物理化学学报 >> 2018, Vol. 34 >> Issue (3): 270-277.doi: 10.3866/PKU.WHXB201707071

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Keggin型多酸负载的单原子催化剂(M1/POM, M = Ni, Pd, Pt, Cu, Ag, Au, POM = [PW12O40]3-)活化氮气分子的密度泛函理论计算研究

尹玥琪,蒋梦绪,刘春光*()   

  • 收稿日期:2017-05-22 发布日期:2017-12-18
  • 通讯作者: 刘春光 E-mail:liucg407@163.com
  • 基金资助:
    国家自然科学基金(21373043)

DFT Study of POM-Supported Single Atom Catalyst (M1/POM, M = Ni, Pd, Pt, Cu, Ag, Au, POM = [PW12O40]3-) for Activation of Nitrogen Molecules

Yueqi YIN,Mengxu JIANG,Chunguang LIU*()   

  • Received:2017-05-22 Published:2017-12-18
  • Contact: Chunguang LIU E-mail:liucg407@163.com
  • Supported by:
    the Natural Science Foundation of China(21373043)

摘要:

采用量子化学密度泛函理论(DFT)结合自然键轨道(NBO)分析的方法对一系列以多酸为载体的单原子催化剂(SACs)(M1/POM (M = Ni, Pd, Pt, Cu, Ag, Au, POM = [PW12O40]3-)的分子几何、电子结构及红外光谱进行计算。结果表明,Pt1/POM对N2分子具有潜在的活化能力,Pt1/POM与N2相互作用主要来自于由金属Pt的dxzdyz轨道与N2π*反键轨道重叠,金属Pt的dxzdyz轨道上的电子填充到了氮气的π*反键轨道上弱化了N≡N成键,导致了N≡N之间的键长增大,有效的活化了氮气分子。对它们红外光谱的分析表明,Keggin型多酸负载金属后W―Oc―W振动吸收峰发生劈裂,产生了五个典型的红外特征吸收峰。

关键词: 单原子催化剂, 人工固氮, 密度泛函理论, 电子结构, 红外光谱

Abstract:

Molecular geometries, electronic structure, and infrared spectroscopy of a series of polyoxometalate (POM)-supported single atom catalyst (SACs) (M1/POM (M = Ni, Pd, Pt, Cu, Ag, Au, POM = [PW12O40]3-) have been studied based on density factional theory (DFT) combined with natural bond orbital (NBO) analysis method. The results show that Pt1/POM has a higher reactivity for activation of N2 relevant to the others. The interaction between the isolated Pt atom and N2 arises from an orbital mixture, which is formed by the dxz and dyz orbital of Pt atom and the π* anti-bond orbit of N2 molecule. The electron transfer from Pt atom to the nitrogen molecule leads to a weakened N≡N bond. The N≡N bond distance increases when compared with the free N2 molecule. All results indicate an effective activation of the nitrogen molecules. For DFT-derived IR spectra, the four characteristic peaks of Keggin-type POM split into five because of introduction of the isolated metal atom.

Key words: Single atom catalyst, Artificial nitrogen fixation, Density functional theory, Electronic structure, Infrared spectroscopy

MSC2000: 

  • O641