The effect of different solvents on the morphology and gas-sensitive properties of tungsten oxide nanoparticles

In this research, tungsten oxide nanocrystals with polymerized spherical, rod, and sheet structures were synthesized using a solvothermal method with WCl₆ as the tungsten source in three different solvent environments: ethanol, an ethanol/water mixture, and pure water. The size and morphology of the tungsten oxide nanocrystals were tuned in a cost-effective manner. Polymerized spherical tungsten oxide synthesized in ethanol consisted of nanorods with diameters of 6–10 nm; rod-shaped tungsten oxide with diameters of 150–260 nm was obtained in the ethanol/water mixture; and sheet-like tungsten oxide synthesized in pure water had dimensions of 50–100 nm × 40–200 nm. Gas sensitivity tests revealed that the synthesized materials were highly selective for acetone, with the polymerized spherical tungsten oxide showing a sensitivity as high as 25.4 at 100 ppm acetone concentration. This difference in gas-sensing properties is attributed to variations in the microstructure and crystal properties of tungsten oxide nanocrystals formed under different solvent conditions. This research provides a new perspective for the design and optimization of gas sensor materials, demonstrating that modulating the solvent type can optimize gas-sensitive performance, which is of significant research importance.

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