催化学报

催化学报 ›› 2010, Vol. 31 ›› Issue (10): 1286-1292.DOI: 10.3724/SP.J.1088.2010.00415

• 研究论文 • 上一篇    下一篇

利用价键和周期密度泛函理论研究 MoVTeNbO 复合氧化物 (M1 相) 催化剂的活性中心

朱艺涵, 陆维敏, 董雪, 王阳, 马飞   

  1. 浙江大学催化研究所, 浙江省应用化学重点实验室, 浙江杭州 310028
  • 收稿日期:2010-10-25 出版日期:2010-10-25 发布日期:2014-03-04

A Combined Bond-Valence and Periodic DFT Study of the Active Sites in M1 Phase of MoVTeNbO Composite Oxide Catalyst

ZHU Yihan, LU Weimin*, DONG Xue, WANG Yang, MA Fei   

  1. Institute of Catalysis, Zhejiang Provincial Key Laboratory of Applied Chemistry, Zhejiang University, Hangzhou 310028, Zhejiang, China
  • Received:2010-10-25 Online:2010-10-25 Published:2014-03-04

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摘要： 采用价键分析和周期密度泛函理论相结合的方法, 研究了具有 M1 晶相结构的 MoVTeNbO 复合氧化物催化剂中各活性中心的 d 电子性质. 通过分析各活性中心配对出现的 d 电子和氧缺位的可能分布, 得到了最可能高效完成丙烷选择氧化反应的 M-M-Te(M = Mo 或 V) 活性中心组合. 此外, 根据各活性中心对骨架稳定的贡献, 说明了稳定的 M1 相骨架主要来自 MoO6 八面体中赤道面上的强共价 Mo–O 键, 而 VO6 八面体的贡献较小. 通常被认为稳定 M1 相的 Nb 物种主要以离子键的形式存在于五边形孔道中, 因而 Nb5+作为一种模板离子, 诱导五边形孔道乃至 M1 晶相结构的生成.

关键词: 丙烷, 选择氧化, 钼, 钒, 碲, 铌, 复合氧化物, 价键, 密度泛函理论, 活性中心

Abstract: A combined bond-valence and periodic DFT study was carried out to interpret the nature of the d electrons in the active sites of the MoVTeNbO composite oxide catalyst (M1 phase). On investigating all the possible distribution of the coupled d electrons and oxygen vacancies, the most efficient combination of M-M-Te (M = Mo or V) active sites for propane selective oxidation has been argued. Besides, MoO6 octahedra primarily stabilizes the crystal structure of M1 phase by attaining strong covalent Mo–O bonding in the equatorial plane, while VO6 octahedra plays a minor role. Nb species that has been considered to stabilize the M1 phase was found to have mainly ionic inter-actions with the framework and act as a structure-directing agent in forming the pentagonal channels in the M1 phase.

Key words: propane, selective oxidation, molybdenum, vanadium, tellurium, niobium, composite oxide, bond-valence, density-functional theory (DFT), active site