Oxidative Coupling of Methane (OCM) by SiO2-Supported Tungsten Oxide Catalysts Promoted with Mn and Na

By Daniyal Kiani, Sagar Sourav, J. Baltrusaitis, I. Wachs. ACS Catalysis, 2019

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The literature for the oxidative coupling of methane (OCM) on supported Mn/Na2WO4/SiO2 catalysts is systematically and critically reviewed. The influence of the precursors, starting SiO2 support crystallinity, synthesis method, calcination temperature, and OCM reaction conditions on the catalyst structure is examined. The supported Mn/Na2WO4/SiO2 catalyst system is found to be dynamic with the catalyst structure quite dependent on the set of variables. Although almost all of the reported studies have determined the catalyst crystalline structures under ambient conditions (room temperature and air exposed), recent in situ/operando characterization study under OCM reaction conditions revealed that all previously detected crystalline phases of the active Mn–Na–W–O components are not present because the reaction temperature is above the melting points of their oxides. The presence of Na also induces the crystallization of the silica support to SiO2 (cristobalite) at elevated temperatures. The nature of the su...

Subfields: Catalysis, Inorganic Chemistry, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/b9094ef07d194cbbaad91ea66589946306a1de44