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Nickel antimonate (NiSb2O6) was synthesized by a microwave-assisted wet chemical method for its application as a potential gas sensor. The powders calcined at 600 °C were corroborated by X-ray diffraction. The microstructure of the material was analyzed by electron microscopy in its scanning and transmission versions, finding different morphologies. The average size of the nanoparticles was estimated at ~ 14.3 nm. X-ray photoelectron spectroscopy showed that the bond energies for Ni (2p) were of 855.2 and 872.9 eV, for Sb, they were of 530.28 and 539.66 eV, and for O(1s), it overlapped the Sb at 530.28 eV. Photoluminescence and UV-Vis spectroscopy measurements confirmed that the emission energy values were of 2.8 and 1.4 eV. Tests carried out in propane and CO atmospheres indicated that the NiSb2O6 nanoparticles possess good response at several concentrations and temperatures of both gases. According to our results, NiSb2O6 is a strong candidate to be applied as a gas sensor. [ABSTRACT FROM AUTHOR]

Nanoparticles of manganese antimonate (MnSb2O6) were prepared using the microwave-assisted colloidal method for its potential application as a gas sensor. For the synthesis of the oxide, manganese nitrate, antimony chloride, ethylenediamine and ethyl alcohol (as a solvent) were used. The precursor material was calcined at 800 °C in air and analyzed by X-ray diffraction. The oxide crystallized into a hexagonal structure with spatial group P321 and cell parameters a = b = 8.8054 Å and c = 4.7229 Å. The microstructure of the material was analyzed by scanning electron microscopy (SEM), finding the growth of microrods with a size of around ~10.27 μm and some other particles with an average size of ~1.3 μm. Photoacoustic spectroscopy (PAS) studies showed that the optical energy band (Eg) of the oxide was of ~1.79 eV. Transmission electron microscopy (TEM) analyses indicated that the size of the nanoparticles was of ~29.5 nm on average. The surface area of the powders was estimated at 14.6 m2/g by the Brunauer–Emmett–Teller (BET) method. Pellets prepared from the nanoparticles were tested in carbon monoxide (CO) and propane (C3H8) atmospheres at different concentrations (0–500 ppm) and operating temperatures (100, 200 and 300 °C). The pellets were very sensitive to changes in gas concentration and temperature: the response of the material rose as the concentration and temperature increased. The results showed that the MnSb2O6 nanoparticles can be a good candidate to be used as a novel gas sensor. [ABSTRACT FROM AUTHOR]