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Characterization of Mn–Na2WO4/SiO2 and Mn–Na2WO4/MgO catalysts for the oxidative coupling of methane

“…Also the Mn 2 O 3 can be substituted for other transition metal oxides, such as those of Fe, Co, Nb, and Zn [22,32], or even rare earth oxides, such as CeO 2 [10], but Mn 2 O 3 is the most effective of the metal oxides tested in the OCM reaction.…”

“…Detailed investigations have examined the influence of each component, i.e. Mn, Na and W, on the catalytic activity and selectivity [5][6][7][8][9][10], the effects of reaction pressure [11] and temperature plus CH 4 :O 2 ratio [12], and studies have been conducted to investigate support materials other than SiO 2 [13][14][15][16]. In addition, fluidized bed processing for large scale production has been tested using the Mn-Na 2 WO 4 /SiO 2 catalyst [17][18].…”

“…W-O-Si interactions, or more specifically the interactions between the WO 4 2-tetrahedron and -cristobalite SiO 2 , are crucial in the formation of stable and active surface species [9,19], and the WO 4 2-is further stabilized by Na (or K) [9], which forms Na 2 WO 4 with a distorted WO 4 2-tetrahedron on the support, M a n u s c r i p t potentially part of the active site [20]. Addition of manganese increases the oxygen mobility of the catalysts and enhances exchange between gaseous and surface oxygen [21][22]. While some studies indicate that manganese is not necessary for an active catalyst [6], other studies reveal that there is a correlation between the activity plus selectivity and the surface concentration of manganese [7].…”

Na2WO4/Co–Mn/SiO2 Catalyst for the Simultaneous Production of Ethylene and Syngas from CH4

“…For instance, syngas could be achieved from the partial oxidation or the steam and/or dry reforming of methane [1][2][3][4][5][6][7][8][9][10], and could be used to produce methanol, oxygenated derivatives and gasoline, while C 2 hydrocarbons could be produced by the oxidative coupling of methane [11][12][13][14][15][16][17][18].…”

Critical Influence of BaCO3 on Low Temperature Catalytic Activity of BaCO3/ZrO2 Catalysts for Oxidative Coupling of Methane

“…Wang et al [10] prepared BaCO 3 /La 2 O 3 catalysts by urea combustion method and achieved the well low temperature OCM performance. Dalai [11] had succeeded to apply the thermal effects as an energy source for the low temperature OCM reaction over Mn/Na 2 WO 4 /SiO 2 catalyst. Under the CH 4 /O 2 = 2.0 and 370°C reaction condition, 14% C 2?…”