Mechanochemical Synthesis of TiO₂-CeO₂ Mixed Oxides Utilized as a Screen-Printed Sensing Material for Oxygen Sensor

TiO₂ and CeO₂ are well known as oxygen sensing materials. Despite high sensitivity, the actual utilization of these materials in gas detection remains limited. Research conducted over the last two decades has revealed synergistic effects of TiO₂-CeO₂ mixed oxides that have the potential to improve some aspects of oxygen monitoring. However, there are no studies on the sensing properties of the TiO₂-CeO₂ obtained by mechanochemical treatment. We have tested the applicability of the mechanochemically treated TiO₂-CeO₂ for oxygen detection and presented the results in this study. The sensing layers are prepared as a porous structure by screen printing a thick film on a commercial substrate. The obtained structures were exposed to various O₂ concentrations. The results of electrical measurements showed that TiO₂-CeO₂ films have a significantly lower resistance than pure oxide films. Mixtures of composition TiO₂:CeO₂ = 0.8:0.2, ground for 100 min, have the lowest electrical resistance among the tested materials. Mixtures of composition TiO₂:CeO₂ = 0.5:0.5 and ground for 100 min proved to be the most sensitive. The operating temperature can be as low as 320 °C, which places this sensor in the class of semiconductor sensors working at relatively lower temperatures.