WO₃ Nanoparticles in the 5−30 nm Range by Solvothermal Synthesis under Microwave or Resistive Heating

Abstract

WO 3 nanoparticles in the 5−30 nm range have been prepared by solvothermal treatment of tungsten chloride in benzyl alcohol up to 210 °C followed by annealing in air. The solvothermal treatment has been performed by resistive or microwave heating and leads to agglomerates of tungsten oxide nanoparticles covered by organic residues. As determined by thermogravimetric measurements in air, the organic residues have been removed at 350 °C for samples prepared by microwave heating and at least at 420 °C for those prepared by resistive heating. When resistive heating is used, the specific surfaces are in the 20−90 m 2 /g range corresponding to particles of 10−30 nm, but smaller sizes, 140 m 2 /g of specific surface and 6 nm in diameter, can been obtained by fast microwave heating.