Methane dehydroaromatization over modified Mn/H-ZSM-5 zeolite catalysts: Effect of tungsten as a secondary metal

• Addition of tungsten decreased the methane conversion of 2Mn/H-ZSM-5 catalysts.
• High coke selectivities were obtained with tungsten modified 2Mn/H-ZSM-5 catalysts.
• High aromatic selectivity and lower coke selectivity were obtained with Pt and Ru promoted catalysts.

The influence of tungsten (0.5–1.5 wt.%) on the MDA reaction was investigated at 800 °C. Addition of W to a 2Mn/H-ZSM-5 catalyst led to a decrease in methane conversion from 6 to 4%. An aromatic selectivity of 74% was obtained with the unpromoted catalyst but this decreased (i.e. from 41 to 12%) with increase in tungsten loading. Addition of Pt or Ru to a 1.5 W/2Mn/H-ZSM-5 catalyst led to an increase in aromatic selectivity from 12 to 55% (Pt) or 46% (Ru) while the coke selectivity decreased from 78 to 37% (Pt) or 42% (Ru) due to the hydrogenating activity of Pt and Ru.

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