CHEMICAL SENSORS BASED ON SNO2 AND WO3 FOR THE DETECTION OF FORMALDEHYDE - COOPERATIVE EFFECTS

Sensors containing either one or two oxide phases, SnO2-Sb2O4 and WO3-Sb2O4, have been synthesized with controlled architectures. The biphasic sensors, composed of an active phase for the detection of formaldehyde (SnO2 and WO3) and a non-active phase, but capable of producing oxygen spillover (Sb2O4), show synergy with respect to sensitivity and have a shorter detection time. It is shown that the surface mobility of the oxygen species enables the results to be explained, without excluding the possibility of the formation of a new electronic structure, or of some electroneptivity or surface acidity effects. This suggests that the spillover phenomenon and remote control could be of use in improving the sensor characteristics.