Different nanostructured tungsten oxides synthesized by facile solvothermal route for chlorine gas sensing

By varying different solvents, WO 3 nanoparticles, nanorods, and nanoflakes were synthesized via facile solvothermal processes without structure-directing agent. The as-prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption–desorption measurements. The effect of the polarity of organic solvents used in the synthesis procedure on the morphologies of as-synthesized WO 3 materials was proposed. Gas sensors based on the synthesized products were fabricated and their gas sensing properties were tested towards a variety of target gases. The results indicated that the sensor based on WO 3 nanoparticles exhibited excellent selectivity, better response and recovery behavior and much higher sensitivity toward Cl 2 compared to those based on WO 3 nanorods, and nanoflakes, although three samples have similar specific surface areas. These characteristics are suggested to arise from good crystallinity and high concentration of oxygen vacancy on the surface of WO 3 nanoparticles.