Synthesis of Nanoscale WO 3 by Chemical Precipitation Using Oxalic Acid

The synthesis of nanoscale WO 3 by chemical precipitation with oxalic acid was studied. The obtained powder was characterized by IR-spectroscopy and powder X-ray diffraction, while its thermal behavior was investigated by simultaneous TGA/DSC analysis. It was found that before heat treatment, the precipitate is a mixture of WO 3 ⋅2H 2 O and tungsten oxalate. The heat treatment at 400°C results in oxalate decomposition, while treatment at 500°C gives single-phase WO 3 with monoclinic crystal structure (mean CSR of 36 ± 4 nm, particle length of 50 ± 5 nm, and particle width of 40 ± 4 nm). The electron work function of the surface of prepared WO 3 particles in air was measured using Kelvin-probe force microscopy. It was shown that chemical precipitation of tungsten(VI) oxide using oxalic acid is a promising method for producing the corresponding nanopowder.