Array of Gas Sensors Based on TiO2 Upon Temperature Modulation

The aim of this work is to demonstrate that thermal modulation improves the selectivity of TiO
₂
- 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 TiO
₂
: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, NO
₂
, H
₂
, CH
₄
, C
₃
H
₈
(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 H
₂
, and NO
_x
have been achieved.