A theoretical and experimental study on the dynamic response in propane atmospheres of sensors made from trirutile magnesium antimonate powders

Magnesium antimonate (MgSb₂O₆) powders were synthesized by the colloidal method using microwave radiation for the evaporation of the solvent. This process is simple, cheap, and easy to apply. It does not require sophisticated equipment to control the physical and chemical parameters to obtain the crystalline phase and nanostructured particle sizes. The calcination of the precursor material at 700 °C allowed us to obtain the tetragonal crystalline phase of the MgSb₂O₆, which was corroborated by X-ray diffraction. The compound’s microstructure was analyzed by scanning electron (SEM) and transmission (TEM) microscopies, finding the growth of irregular microparticles of ~ 0.23 μm in size, microrods of ~ 0.41 μm, and nanoparticles with an average size of ~ 25.5 nm. With the compound’s powders, thick films were manufactured and exposed to dynamic air-propane flows (1500 cm³/min–560 ppm) at different voltages (10–100 V) and a constant temperature of 400 °C. The thick films showed variation in electrical resistance and sensitivity as the exposure time was prolonged. During the measurements, it was observed that the electrical resistance decreased as the applied voltage increased, thus evidencing that magnesium antimonate tends to be a type-n semiconductor. Besides, the sensitivity percentage increased as the voltage increased, from 13 to 66% with 10 to 100 V. This result was corroborated theoretically using a linear systems’ first-order mathematical model. Both theory and experiment were consistent when the voltage was low \(\left({V}_{cc}<54 \%\right)\) $\left(V_{\mathit{cc}},<,54,\%\right)$ . However, the measurement error increased at higher voltages \(\left({V}_{cc}>54 \%\right)\) $\left(V_{\mathit{cc}},>,54,\%\right)$ . Notwithstanding, we show that the mathematical analysis can be applied in designing and implementing new propane gas detection devices. Our results suggest that magnesium antimonate could be an excellent candidate to be used as a propane sensor.