Tracing Active Sites in Supported Ni Catalysts during Butene Oligomerization by Operando Spectroscopy under Pressure

详细信息    查看全文

• 作者：Jabor Rabeah ; Jörg Radnik ; Valérie Briois ; Dietrich Maschmeyer ; Guido Stochniol ; Stephan Peitz ; Helene Reeker ; Camille La Fontaine ; Angelika Brückner
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：December 2, 2016
• 年：2016
• 卷：6
• 期：12
• 页码：8224-8228
• 全文大小：331K
• ISSN：2155-5435

文摘

Supported Ni catalysts have been studied during the dimerization of butenes by operando electron paramagnetic resonance (EPR) and in situ X-ray absorption spectroscopy (XAS) at 353 K and up to 16 bar. Single Ni^I/Ni^II shuttles were identified as active sites, whereby the conversion of initial Ni^I to Ni^II by oxidative addition of butene is obviously faster than the re-reduction of Ni^II to Ni^I by reductive elimination of the C8 product, rendering the equilibrium percentage of Ni^I small. At p ≤ 2 bar, Ni^I single sites form inactive Ni⁰ aggregates, while this is suppressed at higher pressure (∼12 bar). A reaction mechanism is proposed.