Synthesis of the oxide NiSb2O6 and its electrical characterization in toxic atmospheres for its application as a gas sensor

In this work, nanoparticles of the trirutile-type oxide NiSb₂O₆ were synthesized for its application as a gas sensor using the colloidal method assisted by microwave radiation. The crystalline evolution of the powders was analyzed by X-ray diffraction, finding the phase NiSb₂O₆ at 600 °C. SEM micrographs revealed the growth of microspheres, microrods, and irregularly shaped particles. Using TEM, the average size of the nanoparticles was calculated at?~?17.1 nm. For dynamic tests, pellets and thick films were made from the powders calcined at 600 °C. For the thick films, alternating current was used at frequencies of 0.1 and 1 kHz in C₃H₈ and CO₂ atmospheres at 360 °C, where the material’s sensitivity magnitude in CO₂ was?~?2.61% (0.1 kHz) and?~?2.97% (1 kHz). In contrast, for C₃H₈, the sensitivity was?~?6.69% (0.1 kHz) and?~?5.12% (1 kHz) on average. For the pellets, direct current signals and volumetric flow rates of 100, 150, and 200 cm³/min of CO at 200 °C were applied, where the sensitivities were?~?24.37,?~?35.33, and?~?40.77%, respectively. In each test, the sensitivity visibly increased when the gases were injected. Likewise, the response and recovery times decreased when the frequency and gas concentration increased. The results obtained for the trirutile-type oxide NiSb₂O₆, which showed good stability, efficiency, and high sensitivity in CO₂, C₃H₈, and CO atmospheres, make it ideal as a toxic gas sensor.