Preparation of Powders Containing Sb, Ni, and O for the Design of a Novel CO and C3H8 Sensor

Abstract

In this work, powders of NiSb2O6 were synthesized using a simple and economical microwave-assisted wet chemistry method, and calcined at 700, 800, and 900 °C. It was identified through X-ray diffraction that the oxide is a nanomaterial with a trirutile-type structure and space group P42/mnm (136). UV–Vis spectroscopy measurements showed that the bandgap values were at ~3.10, ~3.14, and ~3.23 eV at 700, 800, and 900 °C, respectively. Using scanning electron microscopy (SEM), irregularly shaped polyhedral microstructures with a size of ~154.78 nm were observed on the entire material’s surface. The particle size was estimated to average ~92.30 nm at the calcination temperature of 900 °C. Sensing tests in static atmospheres containing 300 ppm of CO at 300 °C showed a maximum sensitivity of ~72.67. On the other hand, in dynamic atmospheres at different CO flows and at an operating temperature of 200 °C, changes with time in electrical resistance were recorded, showing a high response, stability, and repeatability, and good sensor efficiency during several operation cycles. The response times were ~2.77 and ~2.10 min to 150 and 200 cm3/min of CO, respectively. Dynamic tests in propane (C3H8) atmospheres revealed that the material improved its response in alternating current signals at two different frequencies (0.1 and 1 kHz). It was also observed that at 360 °C, the ability to detect propane flows increased considerably. As in the case of CO, NiSb2O6’s response in propane atmospheres showed very good thermal stability, efficiency, a high capacity to detect C3H8, and short response and recovery times at both frequencies. Considering the great performance in propane flows, a sensor prototype was developed that modulates the electrical signals at 360 °C, verifying the excellent functionality of NiSb2O6.

Photocatalytic Evaluation and Application as a Sensor for the Toxic Atmospheres (Propane and Carbon Monoxide) of Nickel Antimonate (NiSb2O6) Powders

“…In reference [13], the band gap was reported as 3.92 eV. Another study [29] reported values in the range of 2.6-2.8 eV for a material calcined at 700 • C and 2.8-2.9 eV for a material calcined at 900 • C. It should be noted that the forbidden band value is strongly influenced by the synthesis method and the heat treatment employed, as mentioned by several authors [13,22,29], which is consistent with the findings of this study.…”

“…The nickel antimonate synthesis was conducted using a wet chemistry method reported in [ 22 , 23 ]. A stoichiometric 2:1 molar ratio of nickel nitrate hexahydrate and antimony trichloride was used.…”

“…The discoloration was monitored at 30 min intervals using a JASCO V-670 UV-vis spectrophotometer. crystallized in a tetragonal trirutile-type crystal structure [22] with cell parameters a = 4.641 Å and c = 9.223 Å, and space group P42/mnm [22,26]. Figure 3 shows pronounced broadening as well as the high intensity of NiSb 2 O 6 's peaks.…”