Cobalt doping effect on TiO₂ sensing properties under C1–C4 alcohols vapors

The aim of this work is to find the adequate thin materials for the development of sensors for C1–C4 alcohols detections. For this aim, titanium oxide (TiO₂) and Cobalt-doped titanium oxide (Co-TiO₂) materials were used. The films were elaborated by the simple co-precipitation route and calcined at 500 °C. The sensitivity toward C1–C4 alcohols of films based sensors was performed using electrical DC and AC measurements at various working temperatures from 200 to 400 °C. The main sensing mechanism of elaborated films was found to be an oxidation reaction between alcohols vapors and pre-adsorbed oxygen located in the grain boundaries regions on the sensitive films surface. The second part of this work was focused on the selectivity of TiO₂ films toward C1–C4 alcohols and the carbon numbers effects on the TiO₂ selectivity. In order to analyze the C1–C4 alcohols responses, magnitudes differences of used layer, morphological, elements composition, and structural were investigated by scanning electron microscopy (SEM), EDS analysis, and X-ray diffraction (DRX). The results show that Co-doped TiO₂ could be a promising material for alcohols detections with highest sensing value about 54 under 100 ppm of ethanol vapor.