ИСТИНА

Metal oxide semiconductors (MOS) functionalized by catalytic noble metals are promising for gas sensors of volatile organic compounds (VOC). However, the relations of materials composition and sensing behavior is unclear. In this work, we compare the sensitivity and selectivity of different MOS and composites MOS/Au, MOS/Pt to methanol and acetone. Nanoparticles of p-type (NiO, CuO, Co3O4) and n-type (In2O3, ZnO, SnO2, TiO2, and WO3) MOS were obtained by conventional aqueous deposition method. Active sites (surface oxygen species and acid sites) were analyzed. Metal-oxygen bond energy (EM-O) was chosen as a descriptor for the observed difference in active sites concentration and gas sensitivity. The interaction routes of methanol and acetone with materials surfaces were examined by diffuse-reflectance infrared spectroscopy (DRIFT). Oxidation of methanol and acetone to CO, formate and acetate species was revealed, roles of active sites in these reactions were rationalized.