Synthesis of tungsten oxide in ionic liquids via sol-gel and microwave-assisted approaches

Document Type : Original Article

Authors

1 Physical Chemistry Department, National Research Centre

2 Inorganic Chemistry Department, National Research Centre

Abstract

The first results of the synthesis of tungsten oxide nanoparticles in four different ionic liquids namely, 1-ethyl-3-methyl-imidazolium tri-fluoromethylsulfonate ([EMIm]TfO), 1-butyl-1-methyl-pyrrolidinium tri-fluoromethylsulfonate ([Py1,4]TfO), 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)amide ([EMIm]TFSA), and 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)amide ([Py1,4]TFSA), are shown. Two different synthesis methods, sol gel and microwave-assisted, were employed. The sol-gel as-synthesized samples exhibited different XRD patterns based on the ionic liquids type. However, after calcination at 500 oC, monoclinic phase of tungsten trioxide WO3 was obtained. The calcined samples obtained in the employed ionic liquids showed tiny particles of WO3. The microwave-assisted approach was employed for the preparation of tungsten oxide in the ionic liquids [EMIm]TfO, and [EMIm]TFSA. Tungsten trioxide WO3 was obtained in [EMIm]TFSA, whereas hydrogen tungsten oxide H2WO4 was obtained using the ionic liquid [EMIm]TfO, which transforms into WO3 after calcination at 500 oC.

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