A new CO₂ detection system based on the trirutile-type CoSb₂O₆ oxide

CoSb₂O₆ powders were synthesized by means of the colloidal method, using cobalt nitrate, antimony chloride, ethylenediamine, and ethyl alcohol as reagents. The crystalline phase of the oxide was obtained at 600 °C and analyzed by X-ray diffraction. The CoSb₂O₆ showed a tetragonal crystalline structure with cell parameters a = 4.6495 Å, c = 9.2763 Å, and a P4₂/mnm spatial group. The powders were analyzed by means of field emission scanning electron microscopy, finding microcubes (3D) with sizes of 10–25 µm, and microrods with lengths and diameters of 13–27 and 4.5–13.5 µm, respectively. Thick films prepared with oxide’s powders were exposed to air-CO₂ (100‒100 ppm) atmospheres at 250 °C. Material’s response increased as the CO₂ was injected into the measuring chamber, recording a phase change and an average impedance magnitude (Δ|Z|) of ~ 2.623 kΩ. Low CO₂ concentrations were detected at relatively low temperatures, which turns the CoSb₂O₆ into a potential gas sensor. Taking advantage of this, an electronic device was successfully developed to detect concentrations of CO₂.