Sensing of Organic Vapors by Flame-Made TiO_2 Nanoparticles

摘要

Anatase TiO_2 nanoparticles were produced by flame spray pyrolysis (FSP) and characterized by transmission/scanning electron microscopy, X-ray diffraction and nitrogen adsorption. Thick films (30 — 50 μm) of these powders were prepared by drop-coating technique and tested for sensing of acetone, isoprene and ethanol at 500℃ in dry N_2/O_2. A high n-type sensor signal was recorded at ppm levels of these organic vapors with fast response and recovery times. Heat-treatment at 900℃ caused a nearly complete anatase to rutile transformation and a transition to p-type sensing behavior. The rutile sensor had a poor signal to all hydrocarbons tested and considerably longer recovery times.