Sol–gel cobalt oxide–silica nanocomposite thin films for gas sensing applications

Various metal oxide–silica nanocomposite films have been recently proposed as gas-sensitive materials. This paper presents results on cobalt oxide–SiO2 mesoporous nanocomposite thin films templated by a cationic surfactant. The films were deposited on glass substrate by dip-coating process, using [Co(CH3COO)2]·4H2O and tetraethoxysilane (TEOS) as starting materials. The effect of withdrawal speed, number of layers and thermal treatment on the crystalline structure, morphology, Co-doping states, optical, electrical and gas sensing properties of the thin films has been investigated using X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, optical transmittance and room temperature photoreduction–oxidation data.