Array of Gas Sensors Based on TiO2 Upon Temperature Modulation

Abstract

The aim of this work is to demonstrate that thermal modulation improves the selectivity of TiO2 – based resistive-type gas sensors. The sensors operate upon sinusoidal temperature profile over a temperature range of 240–300°C. Sensor array is composed of nanocrystalline TiO2:Cr (0.1–10 at.% Cr). The switching from n-type to p-type conductivity occurs 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. The results of the Principle Component Analysis, PCA demonstrate that reliable detection and classification of H2, and NOx have been achieved.