Dynamical Properties of a Ru/MgAl2O4 Catalyst during Reduction and Dry Methane Reforming

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• 作者：Jan Kehres ; Jon Geest Jakobsen ; Jens Wenzel Andreasen ; Jakob B. Wagner ; Haihua Liu ; Alfons Molenbroek ; Jens Sehested ; Ib Chorkendorff ; Tejs Vegge
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：October 11, 2012
• 年：2012
• 卷：116
• 期：40
• 页码：21407-21415
• 全文大小：411K
• 年卷期：v.116,no.40(October 11, 2012)
• ISSN：1932-7455

文摘

Combined in situ small- and wide-angle X-ray scattering (SAXS/WAXS) studies were performed in a new laboratory setup to investigate the dynamical properties of a ruthenium/spinel (Ru/MgAl₂O₄) catalyst, w(Ru) = 4 wt %, during the reduction and subsequent dry methane reforming. The Ru particles in the fresh catalyst sample were found to be partially oxidized. High-resolution transmission electron microscopy (HRTEM) indicated a coexistence of pure Ru and RuO₂ nanoparticles. Reduction in hydrogen occurred at a temperature between 373 and 393 K. The mean particle diameter as refined from SAXS of the size regime attributed to scattering from Ru/RuO₂-particles decreases slightly by about 0.2 nm during the reduction. Dry methane reforming experiments were performed in a temperature interval from 723 to 1023 K by applying a gas mixture of carbon dioxide and methane in molar ratio of 3:1. The catalyst did not show any deactivation during the experiment of overall 32 h, indicated by stable turnover frequencies for methane. The mean Ru-particle diameter remained constant during the dry methane reforming experiments, revealing a high sintering stability of the Ru/MgAl₂O₄ catalyst.