15. Semiconductor Metal Oxides Doped with Gold Nanoparticles for Use in Acetone Gas Sensors

Abstract

The effect of nanosized gold particles on the adsorption-sensitive properties of SnO2– Au sensors under the detection of acetone vapors has been studied. Different techniques for the preparation of SnO2–Au nanocomposites with an average Au particle size of 2 nm were applied. It has been found that a fivefold increase in the sensor response to acetone vapors and threshold sensitivity (Сlim) of 0.1 ppm are achieved by adding gold to tin dioxide in the colloidal form during synthesis. While adding gold in ion form (Au (III)) leads to a growth of the sensor response to acetone vapors by 2.7 times and defines Сlim of 0.2 ppm. The slope of the calibration curves of the SnO2–Au sensors allows registering acetone vapors at concentrations ranging from Сlim to 5 ppm. This concentration range can be used for express diagnostics in diabetes. The enhanced sensitivity of SnO2–Au sensors to acetone vapors can be explained by an increase in the adsorption–catalytic activity of tin ions as a result of the modifying effect of sulfate groups and the envolving of highly dispersed gold in the adsorption – catalytic process of oxidation of acetone molecules.