Porous tungsten oxide nanoflakes for highly alcohol sensitive performance

Abstract

Porous tungsten oxide (WO₃) nanoflakes have been synthesized by a simple and green approach in an ambient environment. As a precursor solution a polycrystalline hydrated tungstite (H₂WO₄·H₂O) nanoparticles colloid was first prepared by pulsed-laser ablation of a tungsten target in water. The H₂WO₄·H₂O nanoflakes were produced by 72 h aging treatment at room temperature. Finally, porous WO₃ nanoflakes were synthesized by annealing at 800 °C for 4 h. Considering the large surface-to-volume ratio of porous nanoflakes, a porous WO₃ nanoflake gas sensor was fabricated, which exhibits an excellent sensor response performance to alcohol concentrations in the range of 20 to 600 ppm under low working temperature. This high response was attributed to the highly crystalline and porous flake-like morphology, which leads to effective adsorption and desorption, and provides more active sites for the gas molecules’ reaction. These findings showed that the porous tungsten oxide nanoflake has great potential in gas-sensing performance.