Single-Site VOx Moieties Generated on Silica by Surface Organometallic Chemistry: A Way To Enhance the Catalytic Activity in the Oxidative Dehydrogenation of Propane

详细信息    查看全文

• 作者：Samir Barman ; Niladri Maity ; Kushal Bhatte ; Samy Ould-Chikh ; Oliver Dachwald ; Carmen Haeßner ; Youssef Saih ; Edy Abou-Hamad ; Isabelle Llorens ; Jean-Louis Hazemann ; Klaus Köhler ; Valerio D’ Elia ; Jean-Marie Basset
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：September 2, 2016
• 年：2016
• 卷：6
• 期：9
• 页码：5908-5921
• 全文大小：801K
• 年卷期：0
• ISSN：2155-5435

文摘

We report here an accurate surface organometallic chemistry (SOMC) approach to propane oxidative dehydrogenation (ODH) using a μ²-oxo-bridged, bimetallic [V₂O₄(acac)₂] (1) (acac = acetylacetonate anion) complex as a precursor. The identity and the nuclearity of the product of grafting and of the subsequent oxidative treatment have been systematically studied by means of FT-IR, Raman, solid-state (SS) NMR, UV–vis DRS, EPR and EXAFS spectroscopies. We show that the grafting of 1 on the silica surface under a rigorous SOMC protocol and the subsequent oxidative thermal treatment lead exclusively to well-defined and isolated monovanadate species. The resulting material has been tested for the oxidative dehydrogenation of propane in a moderate temperature range (400–525 °C) and compared with that of silica-supported vanadium catalysts prepared by the standard impregnation technique. The experimental results show that the catalytic activity in propane ODH is strongly upgraded by the degree of isolation of the VO_x species that can be achieved by employing the SOMC protocol.