Synthesis and characterization of ultrafine tungsten and tungsten oxide nanoparticles by a reverse microemulsion-mediated method

Ultrafine tungsten and tungsten oxide powders with controllable particle size and structure have been synthesized by a reverse microemulsion-mediated synthesis method. The nanoparticles were characterized by transmission electron microcopy, X-ray diffraction, and thermal analysis. Synthesis conditions, including water-to-surfactant ratio, annealing temperature, water-to-alkoxide ratio, and drying method, have been shown to be critical in controlling the size and structure of tungsten nanoparticles. Using the same synthesis technique, carbon-supported metallic tungsten and tungsten oxide nanoparticles with controllable size and dispersion can also be prepared. The ultrafine nanoparticles prepared by this synthesis method may find interesting applications in various fields such as catalysis, electronics, illumination, gas sensors, and so forth.