Response modeling of temperature modulated array of chromium doped nanostructured TiO2 gas sensors

Abstract

The aim of this work is to demonstrate that thermal modulation improves the selectivity of TiO2-based resistive-type gas sensors. Sensor array, operating upon sinusoidal temperature profile over a temperature range of 240-300°C, is comprised of nanocrystalline TiO2:Cr (0.1-10 at.% Cr) semiconductors switching from n-type to p-type at about 1 at.% Cr. Electrical resistance responses to reducing and oxidizing gases such as NO, NO2, H2, CH4, C3H8 (0-3000 ppm) are dynamically recorded and compared in order to assess cross-sensitivity as well as humidity interference. Theoretical model developed for simple gas-solid interactions is extended to hydrogen.